The html blog » Javascript http://htmlblog.net The web sandbox of Asvin Balloo Mon, 29 Dec 2008 12:01:02 +0000 http://wordpress.org/?v=2.7 en hourly 1 twitree.com - see on which leaves the birds are… http://htmlblog.net/twitreecom-see-on-which-leaves-the-birds-are/ http://htmlblog.net/twitreecom-see-on-which-leaves-the-birds-are/#comments Mon, 29 Dec 2008 12:01:02 +0000 asvin http://htmlblog.net/?p=81 I am happy to announce the launch of twitree.com. It's a twitter application which allows a twitterer to view his followers in a tree-like navigation, which can be expanded.

twitree

twitree makes extensive use of the YUI library. The following components were used :

  • grids css - for the layout
  • yahoo dom event - for DOM and event handling
  • connection manager - for AJAX requests like getting the list of followers for a user
  • container family - to display modal dialogs like prompting for a twitter username, displaying the loading panel
  • JSON utility - to parse the JSON data twitree receives from the twitter servers
  • cookie utility - to fetch username information from a cookie so that the user doesn't have to input his username every time
  • and finally the treeview control which provides a nice tree and dynamically loads the data upon clicking on a node

The application is very much in an initial phase and there are some limitations, like only 100 followers are being returned, rate limiting, etc...

Stay tuned for further information

]]> http://htmlblog.net/twitreecom-see-on-which-leaves-the-birds-are/feed/ Alternate colors to table rows with javascript (YUI) http://htmlblog.net/alternate-colors-to-table-rows-with-javascript-yui/ http://htmlblog.net/alternate-colors-to-table-rows-with-javascript-yui/#comments Tue, 16 Dec 2008 16:49:36 +0000 asvin http://htmlblog.net/?p=71

This article will show you how to add alternate colors to table rows without any server side development or hard coding your scripts, thus providing good readability for your users and great flexibility for you. We will use the YUI library for that.

Demo
Download the demo

The HTML

We need to create our basic HTML file containing a table and adding a class name to it.

 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<title>Alternate colors</title>
	</head>
	<body>
<table class="alternateRows">
<tr>
<td>First Row</td>
</tr>
<tr>
<td>Second Row</td>
</tr>
<tr>
<td>Third Row</td>
</tr>
<tr>
<td>Fourth Row</td>
</tr>
<tr>
<td>Fifth Row</td>
</tr>
</table>
 
	</body>
</html>
 

The Javascript

Next we need to include the YUI libraries, served from their CDN. We need the

  • YAHOO global object which contains a number of methods that are used throughout the library
  • DOM collection which provides methods that simplify common DOM-scripting tasks, including element positioning and CSS style management
  • Event utility for various event handling
 
<!-- Combo-handled YUI JS files: -->
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js"></script>
 

And also our javascript file, alternate.js

 
<script type="text/javascript" src="alternate.js"></script>
 

So our HTML page looks like this:

 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<!-- Combo-handled YUI JS files: -->
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js"></script>
		<script type="text/javascript" src="alternate.js"></script>
		<title>Alternate colors</title>
	</head>
	<body>
<table class="alternateRows">
<tr>
<td>First Row</td>
</tr>
<tr>
<td>Second Row</td>
</tr>
<tr>
<td>Third Row</td>
</tr>
<tr>
<td>Fourth Row</td>
</tr>
<tr>
<td>Fifth Row</td>
</tr>
</table>
 
	</body>
</html>
 

Invoking the javascript

To add the alternate colors to your table rows, you just have to put the following javascript code in your HTML page.

 
	YAHOO.util.Event.on(window, 'load', function(){
		YAHOO.htmlblog.alternateRows.init('alternateRows', '#fff', '#ccc');
	});
 

That means that after the page has been loaded, we call the alternateRows.init function, with 3 parameters:

  • the table class name, in our case it's "alternateRows"
  • the first color in hex, e.g #fff
  • the second color in hex, e.g #ccc




Our complete HTML page

 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<!-- Combo-handled YUI JS files: -->
<script type="text/javascript"src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js"></script>
		<script type="text/javascript" src="alternate.js"></script>
		<script type="text/javascript">
			YAHOO.util.Event.on(window, 'load', function(){
				YAHOO.htmlblog.alternateRows.init('alternateRows', '#fff', '#ccc');
			});
		</script>
		<title>Alternate colors</title>
	</head>
	<body>
<table class="alternateRows">
<tr>
<td>First Row</td>
</tr>
<tr>
<td>Second Row</td>
</tr>
<tr>
<td>Third Row</td>
</tr>
<tr>
<td>Fourth Row</td>
</tr>
<tr>
<td>Fifth Row</td>
</tr>
</table>
 
	</body>
</html>
 

Demo
Download the demo

]]> http://htmlblog.net/alternate-colors-to-table-rows-with-javascript-yui/feed/ Bubble menu javascript or playing with YUI’s event delegation http://htmlblog.net/bubble-menu-javascript-or-playing-with-yuis-event-delegation/ http://htmlblog.net/bubble-menu-javascript-or-playing-with-yuis-event-delegation/#comments Mon, 24 Nov 2008 15:10:41 +0000 asvin http://htmlblog.net/?p=63 bubble
Image courtesy of jobee59's photostream

Event delegation refers to the use of a single event listener on a parent object to listen for events happening on its children (or deeper descendants). Event delegation allows developers to be sparse in their application of event listeners while still reacting to events as they happen on highly specific targets. This proves to be a key strategy for maintaining high performance in event-rich web projects, where the creation of hundreds of event listeners can quickly degrade performance. More on event delegation including examples.

This post illustrates the use of event delegation to create a "bubble" menu, inspired by Bedrich Rios' post on Nettuts.

Demo
Download sample file



The HTML

We'll need the following components from the YUI library:

So our basic HTML page is like this:

 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<!-- Combo-handled YUI JS files: -->
		<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js&2.6.0/build/animation/animation-min.js"></script>
	</head>
	<body>
 
	</body>
</html>
 

Next we'll add some structural markup, a simple list, with "menu" as class name and with 5 items.

 
<ul class="menu">
<li>Menu item 1</li>
<li>Menu item 2</li>
<li>Menu item 3</li>
<li>Menu item 4</li>
<li>Menu item 5</li>
</ul>
 

Updated HTML page:

 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<!-- Combo-handled YUI JS files: -->
		<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js&2.6.0/build/animation/animation-min.js"></script>
	</head>
	<body>
<ul class="menu">
<li>Menu item 1</li>
<li>Menu item 2</li>
<li>Menu item 3</li>
<li>Menu item 4</li>
<li>Menu item 5</li>
</ul>
 
	</body>
</html>
 

The Javascript

Then we just have to add the bubble.js javascript file to our page and it's done, we'll have a nice "bubble" menu.

 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<!-- Combo-handled YUI JS files: -->
		<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.6.0/build/yahoo-dom-event/yahoo-dom-event.js&2.6.0/build/animation/animation-min.js"></script>
		<!-- our bubble file -->
		<script type="text/javascript" src="bubble.js"></script>
	</head>
	<body>
<ul class="menu">
<li>Menu item 1</li>
<li>Menu item 2</li>
<li>Menu item 3</li>
<li>Menu item 4</li>
<li>Menu item 5</li>
</ul>
 
	</body>
</html>
 

bubble.js

 
/**
*	Bubble Menu
*	@author Asvin Balloo (http://htmlblog.net)
*/
bubbleMenu = {
	// private variables
	// class name of our menu
	menuClassName: null,
	// by how much we are sliding
	moveToLength : 10,
 
	/**
	*	Init the whole process here
	*	@method init
	*	@params menuClassName {string} class name of our menus
	*/
	init: function(menuClassName){
		// set our class name to be used later one
		bubbleMenu.menuClassName = menuClassName;
 
		// get all the lists with the class name
		var list = YAHOO.util.Dom.getElementsByClassName(menuClassName);
 
		// loop through them
		for(var i=0; i
<list.length; i++) {
			// add the onmouseover event to it, call the mouseOverHandler function
			YAHOO.util.Event.on(list[i], "mouseover", bubbleMenu.mouseOverHandler);
 
			// get the first child and its padding left for future reference. Useful when using onmouseout to 
 
restore the item to original state
			var listItems = list[i].getElementsByTagName('li');
			var startingPadding = parseInt(YAHOO.util.Dom.getStyle(listItems[0], 'paddingLeft'));
 
			// add the onmouseout event, call the mouseOutHandler function
			YAHOO.util.Event.on(list[i], "mouseout", bubbleMenu.mouseOutHandler, {'list':list[i], "padding" : 
 
startingPadding});
		}
	},
 
	/**
	*	Mouse over handler
	*	@params e {Event} the event
	*/
	mouseOverHandler: function(e){
		// get the target
		var elTarget = YAHOO.util.Event.getTarget(e);
 
		// calculate the current padding left
		var paddingLeft = parseInt(YAHOO.util.Dom.getStyle(elTarget, 'paddingLeft'));
 
		// call the delegate method, with the target and the padding left value
		bubbleMenu.delegate(elTarget, paddingLeft);
	},
 
	/**
	*	Mouse out handler
	*	@params e {Event} the event
	*	@params o {JSON} JSON data containing the list + padding value, eg. {'list': mylist, 'padding': 10}
	*/
	mouseOutHandler: function(e, o){
		// get the target
		var elTarget = YAHOO.util.Event.getTarget(e);
 
		// calculate the left padding, the original padding value - by how much we have padded
		var paddingLeft = o.padding - bubbleMenu.moveToLength;
 
		// call the delegate method with the target and padding value
		bubbleMenu.delegate(elTarget, paddingLeft);
	},
 
	/**
	*	Cool things go here, like animation
	*	@params elTarget {Target} our target
	*	@params padding {Int} by how much we are going to padd
	*/
	delegate: function(elTarget, padding){
		//walk up the DOM tree looking for an <li> in the target's ancestry; desist when you reach the container with our class name
		while (elTarget.className != bubbleMenu.menuClassName) {
			// are you an LI?
			if(elTarget.nodeName.toUpperCase() == "LI") {
				// if so then animate, set the attributes, in our case the left padding
				var attributes = { paddingLeft: {"to": [padding + bubbleMenu.moveToLength] } };
 
				// create our animation
				var anim = new YAHOO.util.Motion(elTarget, attributes, 0.6, YAHOO.util.Easing.bounceOut);
 
				// then animate
				anim.animate();
				break;
			}
			else {
				// it's not an li, so we keep looking and looking
	            elTarget = elTarget.parentNode;
	        }
		}
	}
};
 
// init the whole thing here
YAHOO.util.Event.on(window, "load", function(){
	bubbleMenu.init("menu");
});
 

You can have unlimited (don't abuse) number of bubble menus by just adding the "menu" class to each one of them and including the bubble.js file.
If you're not happy with the menu class or you found another cool class name, then you'll have to update the bubble.js file towards the end:

 
// init the whole thing here
YAHOO.util.Event.on(window, "load", function(){
	bubbleMenu.init("mycoolclass");
});
 

Also you can modify by how much an item slides by modifying the moveToLength variable (default 10):

 
 
// by how much we are sliding
moveToLength : 30,
 

Note that the demo is using reset-fonts-grids CSS and the page has been styled with the following:

 
body {
	margin: 0;
	padding: 0;
	background: #1d1d1d;
	font-family: "Lucida Grande", Verdana, sans-serif;
	font-size: 100%;
}
 
.menu li{
	padding-left: 20px;
	line-height: 2em;
	width: 150px;
	color: #999;
 
	background: #222;
	border: 1px solid #1a1a1a;
	-moz-border-radius: 10px;
}
 
]]> http://htmlblog.net/bubble-menu-javascript-or-playing-with-yuis-event-delegation/feed/ 8 practical tips to make your web pages faster http://htmlblog.net/8-practical-tips-to-make-your-web-pages-faster/ http://htmlblog.net/8-practical-tips-to-make-your-web-pages-faster/#comments Thu, 06 Nov 2008 16:36:23 +0000 asvin http://htmlblog.net/?p=40

Yahoo's Exceptional Performance team has compiled a list of 34 best practices to have faster web pages. In this post I'll show you 8 tips which helped me to get a B grade in YSlow! for web pages that I develop. Currently YSlow's web page analysis is based on 13 identified basic rules that affect web page performance. In decreasing order of priority they are:

  1. Make Fewer HTTP Requests
  2. Use a Content Delivery Network
  3. Add an Expires Header
  4. Gzip Components
  5. Put CSS at the Top
  6. Move Scripts to the Bottom
  7. Avoid CSS Expressions
  8. Make JavaScript and CSS External
  9. Reduce DNS Lookups
  10. Minify JavaScript
  11. Avoid Redirects
  12. Remove Duplicate Scripts
  13. Configure ETags

You can get more info by clicking on each item. Of course using a CDN is not affordable by everybody, including me. This didn't prevent me to have a B grade though. I will guide you through some of the items which worked for me.

Make Fewer HTTP Requests
If you're using the YUI library, the good news is that recently the team graciously offered a Combo Handler Service, served from their CDN. This helps us to eliminate HTTP requests by requesting a single file. For example, to use the Rich Text editor, it needed 6 separate HTTP requests:

 
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/yahoo-dom-event/yahoo-dom-event.js"></script>
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/container/container_core-min.js"></script>
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/menu/menu-min.js"></script>
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/element/element-beta-min.js"></script>
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/button/button-min.js"></script>
<script type="text/javascript" src="http://yui.yahooapis.com/2.5.2/build/editor/editor-beta-min.js"></script>
 

Now with the Combo Handler service, it has been stripped to only 1 file:

 
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js&2.5.2/build/container/container_core-min.js&2.5.2/build/menu/menu-min.js&2.5.2/build/element/element-beta-min.js&2.5.2/build/button/button-min.js&2.5.2/build/editor/editor-beta-min.js"></script>
 

If you're not using the YUI library or not interested in using the Combo Handler service, you can try Minify!
Minify is a PHP5 app that can combine multiple CSS or Javascript files, compress their contents (i.e. removal of unnecessary whitespace/comments), and serve the results with HTTP encoding (gzip/deflate) and headers that allow optimal client-side caching.

Another tool which can be helpful is Dojo Shrinksafe which not only minifies your javascript code but also allows you to upload several javascript files and have them compressed in 1 single file.

Another way to make fewer HTTP requests is by using CSS sprites which are big images containing lots of smaller ones. An online tool which can make CSS sprites out of your smaller ones is the CSS Sprite Generator. You just have to upload your pics and it will generate your sprite together with the CSS code. More info about CSS sprites can be found on CSS Tricks.

Add an Expires Header
For this to work on Apache, you'll need to have mod_expires enabled. Then create an .htaccess file or edit your httpd.conf with the following content:

 
ExpiresActive On
ExpiresByType image/jpg "access plus 2 years"
ExpiresByType image/jpeg "access plus 2 years"
ExpiresByType image/gif "access plus 2 years"
ExpiresByType application/javascript "access plus 2 years"
ExpiresByTYpe text/css "access plus 2 years"
 

In the above listing, all images(jpg/jpeg/gif) will have an expires header 2 years in the future.

Gzip Components
You must have mod_deflate enabled and drop these lines in your httpd.conf file

 
SetOutputFilter DEFLATE
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary
 
Put CSS at the Top
All CSS must be between your head tag, like that :

 
	<html>
		<head>
<link rel="stylesheet" href="style.css" type="text/css" media="screen" />
		</head>
		<body>
 
		</body>
	</html>
 
Move Scripts to the Bottom
While the CSS are sitting at the top of your page, javascripts must be moved towards the lower part of your page, typically in the body tag. I usually put them before the closing body tag.

 
	<html>
		<head>
		</head>
		<body>
		...
		...
		<script type="text/javascript" src="myjs.js"></script>
		</body>
	</html>
 
Reduce DNS Lookups
I don't usually have more than 2 DNS lookups in my scripts, else YSlow will be removing some points.

Minify JavaScript
As I mentioned earlier on, Dojo Shrinksafe is an online tool which minifies your code.

Another great command line tool is Julien Lecomte YUI Compressor.

In order to use it you must have Java installed (>= 1.4).

Douglas Crockford also has something similar in JSMin

Configure ETags
Just drop this line in your httpd.conf:

 
FileETag None
 

;-)

]]> http://htmlblog.net/8-practical-tips-to-make-your-web-pages-faster/feed/ Pixidou - an Open Source AJAX Image Editor (PHP and YUI based) http://htmlblog.net/pixidou-an-open-source-ajax-image-editor-php-and-yui-based/ http://htmlblog.net/pixidou-an-open-source-ajax-image-editor-php-and-yui-based/#comments Fri, 31 Oct 2008 17:42:09 +0000 asvin http://htmlblog.net/?p=37 Pixidou is a new open source AJAX image editor which will allow you to :

  • adjust brightness
  • adjust contrast
  • cropping
  • flipping
  • negative
  • resizing
  • rotating
  • tint

images.

What you need to get running

  • PHP5.2+ installed on your webserver
  • GD2
  • a web browser

Demo

Installation
Unzip/untar the software in your web directory and that's all ;-)
Also ensure the images folder is writable by your webserver.
Have fun !!!

Download
Get it and follow it at github

All the image manipulation is PHP-based with the help of the great class.upload.php class by Colin Verot which I highly recommend.

The frontend is the most interesting part, where I've use the one and only YUI library. Here are the component I used (served from Yahoo CDN) :

  • reset-fonts.css - for all resetting, style information
  • utilities - for all AJAX, animation, drag drop, event handling stuff
  • container - for all panels, dialogs, alerts
  • menu - for the top navigation menu together with the submenus
  • button - provides nice buttons
  • slider - for adjusting contrast and brightness
  • color picker - to choose the color to tint the image
  • resize - to resize the image
  • image cropper - image cropping utility
  • json - to parse all JSON data returned from PHP scripts
  • layout - the general layout
  • tabview - for the about information

I've not used the grids.css since it caused some problems while using the color picker.

It's only the beginning of Pixidou and I'am currently looking for some collaborators. So, if you think you can give a helping hand in any way to Pixidou, don't hesitate to contact me (asvin.balloo [@] gmail.com), I'll happily add you as a contributor to the repository on github.

Since it's an early version, there must be some bugs lying everywhere, don't hesitate to drop me an email.

]]> http://htmlblog.net/pixidou-an-open-source-ajax-image-editor-php-and-yui-based/feed/ AJAX image cropper with YUI and PHP http://htmlblog.net/ajax-image-cropper-with-yui-and-php/ http://htmlblog.net/ajax-image-cropper-with-yui-and-php/#comments Wed, 08 Oct 2008 11:01:55 +0000 asvin http://htmlblog.net/?p=35

This post will show you how to build an AJAX crop image tool using the image cropper control from YUI library and PHP.

Demo
Download sample file

The ImageCropper Control from the YUI library gives you an interactive interface for getting the dimensions to crop an image and using these dimensions in PHP, we can do some cropping.

The script we are going to build will

  • allow users to upload an image via AJAX
  • then allow them to select an area for cropping
  • lastly, provide a download link for the cropped image.

There are 3 files we are going to use

  • index.php - will contain the form for image upload as well as the cropping interface
  • upload.php - provides uploading functionality
  • crop.php - provides cropping functionality

From a technical point of view, the flow will be like this :

  1. user uploads jpg image (index.php)
  2. index.php then posts the image asynchronously to upload.php which will do the upload on the server, returning JSON data containing the image file name, its width and its height.
  3. with the JSON data and innerHTML we put the image in our page
  4. initialize the javascript cropping tool
  5. generate a download link (crop.php)


Let's have a look at index.php
The index.php is our main file where users will be able upload images and then download the cropped ones.

We'll need the following components from the YUI library :

  • yahoo-dom-event.js - for DOM manipulation and Event handling
  • dragdrop - dependency for the image cropper control
  • element - dependency for the image cropper control
  • resize - dependency for the image cropper control
  • connection - for AJAX requests, in our case for image uploads via AJAX
  • json - for parsing JSON data
  • imagecropper - our most important control

Of course we'll use Yahoo combo handling and add the js to our page along with the CSS needed for the above controls :

 
<link rel="stylesheet" type="text/css" href="http://yui.yahooapis.com/2.5.2/build/resize/assets/skins/sam/resize.css" />
<link rel="stylesheet" type="text/css" href="http://yui.yahooapis.com/2.5.2/build/imagecropper/assets/skins/sam/imagecropper.css" />
<!-- js -->
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js&2.5.2/build/dragdrop/dragdrop-min.js&2.5.2/build/element/element-beta-min.js&2.5.2/build/resize/resize-beta-min.js&2.5.2/build/imagecropper/imagecropper-beta-min.js&2.
5.2/build/connection/connection-min.js&2.5.2/build/json/json-min.js"></script>
 

Next users must be able to upload images via AJAX, so we add a form to our page:

 
<form action="upload.php" enctype="multipart/form-data" method="post" name="uploadForm" id="uploadForm">
	Image :
<input type="file" name="uploadImage" id="uploadImage" />
<input type="button" id="uploadButton" value="Upload"/>
</form>
 

We have an onclick event to the upload button to fire the uploading process.

 
// add listeners
YAHOO.util.Event.on('uploadButton', 'click', uploader.carry);
 

We'll also need 2 containers :

  • imageContainer - will contain our uploaded image
  • downloadLink - will contain the download link
 
<div id="imageContainer"></div>
<div id="downloadLink"></div>
 

Both containers will be updated via innerHTML afterwards.

AJAX upload
For the AJAX upload, Code Central

has an excellent tutorial which I highly recommend. I took the code sample and modified it a bit to fit my needs. Finally I came up with a nice JSON object called uploader which has one method, carry. The latter just posts form data to a specified URL.

 
uploader = {
	carry: function(){
		// set form
		YAHOO.util.Connect.setForm('uploadForm', true);
		// upload image
		YAHOO.util.Connect.asyncRequest('POST', 'upload.php', {
			upload: function(o){
				// parse our json data
				var jsonData = YAHOO.lang.JSON.parse(o.responseText);
 
				// put image in our image container
				YAHOO.util.Dom.get('imageContainer').innerHTML = '<img id="yuiImg" src="' + jsonData.image + '" width="' + jsonData.width + '" height="' + jsonData.height + '" alt="" />';
 
				// init our photoshop
				photoshop.init(jsonData.image); 
 
				// get first cropped image
				photoshop.getCroppedImage();
			}
		});
	}
};
 

When upload is complete, we get the JSON data we mentioned earlier on. For e.g :

 
{"image" : "images/myimage.jpg", "width" : "500", "height" : 400}
 

With this data and using innerHTML we update our imageContainer div to put our image which will have yuiImg as id :

 
YAHOO.util.Dom.get('imageContainer').innerHTML = '<img id="yuiImg" src="' + jsonData.image + '" width="' + jsonData.width + '" height="' + jsonData.height + '" alt="" />';
 

It's very important to specify the image width and height else the image cropper won't work.
Next we initialize another JSON object, photoshop which we'll have a look now.

Our photoshop object

 
photoshop = {
	image: null,
	crop: null,
 
	init: function(image){
		// set our image
		photoshop.image = image;
 
		// our image cropper from the uploaded image
		photoshop.crop = new YAHOO.widget.ImageCropper('yuiImg');
		photoshop.crop.on('moveEvent', function() {
			// get updated coordinates
			photoshop.getCroppedImage();
		});
	},
 
	getCroppedImage: function(){
		var coordinates = photoshop.getCoordinates();
		var url = 'crop.php?image=' + photoshop.image + '&cropStartX=' + coordinates.left +'&cropStartY=' + coordinates.top +'&cropWidth=' + coordinates.width +'&cropHeight=' + coordinates.height;
		YAHOO.util.Dom.get('downloadLink').innerHTML = '<a href="' + url + '">download cropped image</a>';		
 
	},
 
	getCoordinates: function(){
		return photoshop.crop.getCropCoords();
	}
};
 

The init function iniatializes the YUI image cropper from the uploaded image which has yuiImg as id.

 
photoshop.crop = new YAHOO.widget.ImageCropper('yuiImg');
 

We also subscribe to the moveEvent for the cropper since we'll need to update the download link for the cropped image. So whenever the image cropper is moved/resized, we call the getCroppedImage function.

 
photoshop.crop.on('moveEvent', function() {
	// get updated coordinates
	photoshop.getCroppedImage();
});
 

The getCroppedImage function will generate the download link for the cropped image. To do image cropping in PHP we'll need

  • the image we want to crop
  • the X,Y coordinates
  • height and width of the to be cropped area

Fortunately the YUI cropper utility has a function which will give us what we want, it's the getCropCoords() method. So, whenever the getCroppedImage function is called, we get the coordinates of the cropped area, build a URL and finally put the download link in our downloadLink container.

 
// get coordinates
var coordinates = photoshop.getCoordinates();
 
// build our url
var url = 'crop.php?image=' + photoshop.image + '&cropStartX=' + coordinates.left +'&cropStartY=' + coordinates.top +'&cropWidth=' + coordinates.width +'&cropHeight=' + coordinates.height;
 
// put download link in our page
YAHOO.util.Dom.get('downloadLink').innerHTML = '<a href="' + url + '">download cropped image</a>';
 

This is all we need for the index page.

upload.php

 
if(!empty($_FILES["uploadImage"])) {
  	// get file name
	$filename = basename($_FILES['uploadImage']['name']);
 
	// get extension
  	$ext = substr($filename, strrpos($filename, '.') + 1);
 
  	// check for jpg only
  	if ($ext == "jpg") {
      		// generate unique file name
  		$newName = 'images/'.time().'.'.$ext;
 
  		// upload files
        	if ((move_uploaded_file($_FILES['uploadImage']['tmp_name'], $newName))) {
 
        		// get height and width for image uploaded
        		list($width, $height) = getimagesize($newName);
 
        		// return json data
           		echo '{"image" : "'.$newName.'", "height" : "'.$height.'", "width" : "'.$width.'" }';
        	}
        	else {
           		echo '{"error" : "An error occurred while moving the files"}';
        	}
  	}
  	else {
     		echo '{"error" : "Invalid image format"}';
  	}
}
 

The upload.php file too is self explanatory, we check for a jpg image only, then generate an unique filename, put it in the images folder and finally build json data which we'll use for DOM manipulation. Of course the images folder must be writable by the web server.

crop.php

 
// get variables
$imgfile = $_GET['image'];
$cropStartX = $_GET['cropStartX'];
$cropStartY = $_GET['cropStartY'];
$cropW = $_GET['cropWidth'];
$cropH = $_GET['cropHeight'];
 
// Create two images
$origimg = imagecreatefromjpeg($imgfile);
$cropimg = imagecreatetruecolor($cropW,$cropH);
 
// Get the original size
list($width, $height) = getimagesize($imgfile);
 
// Crop
imagecopyresized($cropimg, $origimg, 0, 0, $cropStartX, $cropStartY, $width, $height, $width, $height);
 
// force download nes image
header("Content-type: image/jpeg");
header('Content-Disposition: attachment; filename="'.$imgfile.'"');
imagejpeg($cropimg);
 
// destroy the images
imagedestroy($cropimg);
imagedestroy($origimg);
 

Crop.php allows us to crop our uploaded image. First we get all the variables passed to us via the AJAX request,

 
// get variables
$imgfile = $_GET['image'];
$cropStartX = $_GET['cropStartX'];
$cropStartY = $_GET['cropStartY'];
$cropW = $_GET['cropWidth'];
$cropH = $_GET['cropHeight'];
 

Then we create 2 images, the original one and the cropped one, and use the imagecopyresized function to generate the cropped image. We add some header information to tell the world it's an image and prompt for a save dialog.

Demo
Download sample file

]]> http://htmlblog.net/ajax-image-cropper-with-yui-and-php/feed/ Show/hide containers by only adding CSS classes without writing javascript code (YUI-based) http://htmlblog.net/showhide-containers-by-only-adding-css-classes-without-writing-javascript-code-yui-based/ http://htmlblog.net/showhide-containers-by-only-adding-css-classes-without-writing-javascript-code-yui-based/#comments Sat, 20 Sep 2008 07:37:49 +0000 asvin http://htmlblog.net/?p=34 html code

This post will show you how to add the collapse/expand functionality in your HTML pages, perfect for FAQs by only adding two class names to your existing page and including the scripts below. Of course it's all YUI-based and also a demo of the fantastic YUI selector utility.

Demo of the toggler
Download the javascript file

What does the script do ?
OK, suppose you have a FAQ page where you have traditional anchor methods, i.e you click on the question and then you go to the bottom of the page to get the answer or you get redirected to another page. But now your users are complaining your site's not trendy enough and want to have the answer displayed immediately after clicking the question.

The solution.
After downloading the javascript file, include it at the bottom of your page with the following HTML code:

 
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js&2.5.2/build/selector/selector-beta-min.js"></script>
<script type="text/javascript" src="js/toggler.js"></script>
 

We need to include the selector utility which will be used to retrieve a collection of elements that match a given CSS selector. For e.g if we want to retrieve all div nodes in HTML page having the class "foo", we can write :

 
var myNodes = YAHOO.util.Selector.query('div.foo');
 

The selector is used in the toggler.js file.

After adding the scripts, now you have to add CSS classes to your containers. For example for the FAQ, for questions (or main, call it whatever you want), you add the class "htmlblog-main" and for the answers (or sub), add the "htmlblog-sub" class.

Before :

 
<div>1. Question</div>
<div>Answer1</div>
<div>2. Question 2</div>
<div>Answer 2</div>
 

After :

 
<div class="htmlblog-main">1. Question</div>
<div class="htmlblog-sub">Answer1</div>
<div class="htmlblog-main">2. Question 2</div>
<div class="htmlblog-sub">Answer 2</div>
 

If you already had a class for that container, no problem you can add the htmlblog-main or htmlblog-sub class :

 
<div class="myclass htmlblog-main">1. Question</div>
 

What next ?
That's all ! All your answer containers will be hidden and questions will have a [+] besides them. Pretty easy

Am I obliged to use the htmlblog-main and html-sub classes ? And I don't want to use div tags, I want li tags.
Don't worry, if you don't like the class names you can put whatever you want but you'll have to edit the toggler.js file at the following lines :

 
YAHOO.util.Event.addListener(window, 'load', function(){
	YAHOO.htmlblog.init('div', 'htmlblog-main', 'htmlblog-sub');
});
 

For e.g, if you're using li tags instead of divs with the "myMainClass" as main and "mySubClass" as sub, the code goes :

 
YAHOO.util.Event.addListener(window, 'load', function(){
	YAHOO.htmlblog.init('li', 'myMainClass', 'mySubClass');
});
 

I'am getting an alert saying "Number of main and subs incorrect".
That means the number of main/subs are not the same. You need to have the number of the main class equals the number of the sub class.

I've commented the toggler.js file and you can easily change it to fit your needs.

Demo of the toggler
Download the javascript file

]]> http://htmlblog.net/showhide-containers-by-only-adding-css-classes-without-writing-javascript-code-yui-based/feed/ nouzil.com - a new Mauritian portal on the web (YUI-based) http://htmlblog.net/nouzilcom-a-new-mauritian-portal-on-the-web-yui-based/ http://htmlblog.net/nouzilcom-a-new-mauritian-portal-on-the-web-yui-based/#comments Wed, 10 Sep 2008 15:25:47 +0000 asvin http://htmlblog.net/?p=32

I came to know the existing of a new Mauritian portal via Avinash called nouzil (which means our island in creole) and I must say at first look it reminds me of Netvibes a lot. I think the nouzil.com team picked up some bits and pieces from Netvibes.com.
Anyway, looking behind the scenes I notice that the new portal uses YUI a lot, in fact it's all YUI-based. Had a look at the source and they are using the following YUI components (with my comments) :