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Archive for the jQuery category

Slideshowify Gets a Project Homepage, Demos, Documentation

posted by admin in Code, CSS, design, HTML, JavaScript, jQuery, jQuery

After just sitting there collecting dust for a while, Slideshowify is back and better than ever.

New updates include CSS3 support (provided via @rstacruz‘s excellent jquery.transit.js plugin), animation as well as zooming in both directions and better browser support – it works and looks great on tablets and other touch devices.

In addition, the project now has a legitimate project homepage which provides documentation and a couple of live demos. 

Check it out now at: http://subchild.com/slideshowify

Processing XML with jQuery – An IBM devWorks Tutorial

posted by admin in Code, JavaScript, jQuery, jQuery, PHP, XML

My tutorial on processing XML with jQuery in the browser is now live on IBM’s developerWorks website. Check it out at:

http://www.ibm.com/developerworks/xml/tutorials/x-processxmljquerytut/index.html

Most JavaScript and jQuery ninjas needn’t read past the title for the gist, but hopefully there’s something new for everyone. Either way, your comments are welcome.

Live XML Editor: Version 1.5

posted by admin in JavaScript, jQuery, PHP, XML
liveXmlEdit_screenshot

I recently had a chance to make a few updates to the Live XML Editor and address some user requests. Version 1.5 is now done and out.  Among the updates are:

- jQuery 1.4 support. Since the editor relies heavily on DOM rendering and events, this update makes the app snappier.

- Comment node display and editing. This was requested by a user and I was surprised that I hadn’t thought of it. Creating comments isn’t supported yet, but its on the to-do list.

- Various bug fixes, tweaks and optimizations.

- Added (MIT) license.

Check it out: http://www.subchild.com/liveXmlEdit.  Code is also on GitHub: http://github.com/subchild/liveXmlEdit/

Slideshowify: Ken Burns Slideshow Effect as a jQuery Plugin

Slideshowify is a jQuery plugin for creating a slideshow of images that will fill the screen with a (cropped) image, then pan across to reveal the rest of it. This is commonly referred to as the Ken Burns Effect and is often seen in documentaries. A nice version is of it can be seen in that Mac screensaver.

Anyhow, here’s a stab at such a thing. Some future enhancements are obvious (pan direction, zooming, transition options, etc.) and anticipate finding the time to add that stuff shortly.

For now, check out the code on github.com and see a demo at www.subchild.com/slideshowify

To use it, include jQuery, jquery.slideshowify.js, then feed slideshowify a selector that matches some images. For example:

$("img").slideshowify();

Alternatively, you could load data from an external feed and call $.slideshowify() with configuration options:

$.slideshowify({
 	dataUrl   : "http://www.gallerama.com/services/gallery/get.php?gid=2107&versions[]=9",
	dataType  : "jsonp",
	randomize : true,
 	filterFn  : function(imgs){
 		var fixedImgs = [];
 		$.each(imgs, function(i, img){
 			fixedImgs.push(img.versions["9"]);
 		});
 		return fixedImgs;
 	},
	afterFadeIn : function(imgData){},
	beforeFadeOut : function(imgData){}
 });

Most of the params here are passed directly to jQuery’s $.ajax() method. Some are used to reformat the data (slideshowify() expects an array of objects of this format: {src:”domain.com/path/to/image.jpg”, w:”600″, h:”400″}), others are hooks or speed (fade, delay) options.

Proper documentation will be provided. Most likely.

Live XML Editor

posted by admin in JavaScript, jQuery, PHP, XML

While I don’t recommend editing XML files by hand, its not an uncommon task and I occasionally find myself having to do it.  As I am a big advocate of web based applications, I was hoping to find a web based XML editor but had trouble finding one.  So I built one.

From the technical point of view, editing the XML directly (rather than translating it to a more edit-friendly format, then converting it back) was something I wanted to explore and jQuery’s fantastic DOM support (which covers XML files as well) seemed to be the right approach.  All of the editing is handled in the browser and each update is reflected in the source XML immediately.  Saving merely consists of pushing the string onto a PHP script which saves the file.

The interface is still a little clunky and could use some visual and functional improvements, but it should get the job done for now.  I’m also planning a number of feature updates.

Let me know how you like.

Go to the Live XML Editor »

jQuery's .live(), Enhanced

posted by admin in JavaScript, jQuery

If you’re not using jQuery’s .live() method you are really missing out. live() works by storing a selector-to-handler mapping in an internal hash which allows it to execute the handler for all existing and future elements which match that selector. This is a fantastic feature, however the current implementation relies on real DOM elements (even if they’re not appended to the document) for access to the selector which slows it down when it really doesn’t need to.

Wouldn’t it be great if it could just store the reference (the “selector”), which would make assigning handlers a constant complexity operation? Its certainly possible, and thanks to Dave Furfero (of blurf.furf.com) you don’t have to wait for a future release of jQuery to use this. (Lets hope they include it.)

Read all about it here:http://blurf.furf.com/2009/09/jquery-live-from-new-york/

Here’s the code:

$.extend({
	live: function(selector, type, fn){
		var jQElem = $(document);
		jQElem.selector = selector;
		jQElem.live(type, fn);
	}
});

Thanks Furf.

How to Get or Set Text Value of an XML Node in JavaScript Using jQuery

posted by admin in JavaScript, jQuery, XML

Edited on October 7th: I realized after the original post that the code provided was not entirely correct.  Specifically, it ignored CDATA values.  Methods below have been updated to reflect that fix.

The logic for extracting the text values is extracted into a separate function:

function getTextNodes(node){
  return $(node).contents().filter(function(){
    return (
      ((this.nodeName=="#text" && this.nodeType=="3") || this.nodeType=="4") // text node, or CDATA node
      && ($.trim(this.nodeValue.replace("\n","")) !== "") // not empty
    );
  });
}

This method first gets the contents of the node (all children, including child nodes, text nodes, comments), and then filters it down to only what it promises to deliver.  It ignores text nodes which contain only blanks, only newlines, or some combination of only those two.

Then, the set/get functions become:

function getNodeValue(node){
   var $textNodes = getTextNodes(node);
       textValue = ($textNodes[0]) ? $.trim($textNodes[0].textContent) : "";
   return textValue;
}

And since we’re at it, here’s a way to set it:

function setNodeValue(node, value){
   var $textNodes = getTextNodes(node);
   if ($textNodes.get(0)) $textNodes.get(0).nodeValue = value;
   else node["textContent"] = value;
}

One other change to note (bolded above, in setNodeValue()) is that if a specific node has no prior text value, instead of setting it using node.textContent, we’re setting it with node["textContent"] since Internet Explorer doesn’t like the first method (property doesn’t exist when blank).  This is good practice since its generally safer.

Best Cheat Sheets for Web Developers

posted by admin in CSS, HTML, JavaScript, jQuery

A colleague of mine sent out a link to a very resourceful page containing very helpful cheat sheets for web developers.  Get them here: http://www.webappers.com/2008/11/05/best-cheat-sheets-for-web-developers/

I haven’t seen the WebAppers site before, but it definitely deserves a bookmark and periodic visits.

Creating Fading Headlines with jQuery in 5 minutes

posted by admin in HTML, JavaScript, jQuery

We see fading headlines on the Apple site as well as lots of news and media websites.  Rather than listing all of headlines in a “stack”, they use much less real estate by having all headlines displayed in a smaller space, with headlines fading in and out over each other.  Whether you like this or not is not the point.  Showing how you can build this quickly, is.

Since I’m a big fan of the jQuery library I decided to see what it would take to build this with the help of this popular JavaScript library.  As expected, it proved to be very simple and I’m posting it here in case someone finds it handy.  It might also serve as a good interview question for candidates who claim to be proficient with JavaScript and jQuery.

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Subchild is a blog about web development. It's author is Aleksandar Kolundzija, himself a web developer for 10++ years, presently a Hacker-in-Residence at betaworks. Prior to betaworks, Alex worked at Google, Meebo, MLB Advanced Media (MLB.com), Razorfish, and elsewhere.

Some of Alex's side projects include Gallerama.com, Slideshowify, LiveXmlEdit, and other blogs like Dopevector and blog.gallerama.com. When he's not working on any of those, Alex is probably playing guitar, producing music, mixing records, taking photos, playing with his kid, or watching documentaries about particle physics, the monetary system, etc.

Let him know what's up: ak @ subchild.com