Treehouse

Use Custom Missing Image Graphics Using Dojo

By on  

A few months back I posted an article about how you can use your own “missing image” graphics when an image fails to load using MooTools and jQuery. Here’s how to do the same using Dojo.

The HTML

<p><img src="http://cnn.com/image-that-doesnt-exist.jpg" alt="Missing 1" class="missing1" /></p>
<p><img src="http://cnn.com/demo/image-that-doesnt-exist-2.jpg" alt="Missing 2" class="missing2" /></p>

We'll delegate the image to display by class -- be sure to give the appropriate class to each image. We'll be using two images for the sake of this demo.

The Dojo JavaScript

dojo.addOnLoad(function() {
	/* version 1 */
	dojo.query('img.missing1').connect('onerror',function() {
		dojo.attr(this,{
			src: 'http://davidwalsh.name/demo/missing-image.jpg',
			alt: 'Sorry!  This image is not available!',
			style:'border: 1px solid #f00;width:110px;height:40px;'
		});
	});
	/* version 2 */
	dojo.query('img.missing2').connect('onerror',function() {
		dojo.attr(this,{
			src: 'http://davidwalsh.name/demo/missing-image-2.jpg',
			alt: 'Sorry!  This image is not available!',
			style:'border: 1px solid #f00;width:30px;height:28px;'
		});
	});
});

We query the DOM for both classes and replace any broken images (we can tell there ways a problem because the onError event fires) with the two designated images. Simple!

Of course you should always do what you can on the server side to prevent broken images -- the small javascript snippet above should be used as a safeguard.

ydkjs-5.png

Recent Features

  • CSS vs. JS Animation: Which is Faster?

    How is it possible that JavaScript-based animation has secretly always been as fast — or faster — than CSS transitions? And, how is it possible that Adobe and Google consistently release media-rich mobile sites that rival the performance of native apps? This article serves as a point-by-point...

  • From Webcam to Animated GIF: the Secret Behind chat.meatspac.es!

    My team mate Edna Piranha is not only an awesome hacker; she's also a fantastic philosopher! Communication and online interactions is a subject that has kept her mind busy for a long time, and it has also resulted in a bunch of interesting experimental projects...

Incredible Demos

  • Check All/None Checkboxes Using MooTools

    There's nothing worse than having to click every checkbox in a list. Why not allow users to click one item and every checkbox becomes checked? Here's how to do just that with MooTools 1.2. The XHTML Note the image with the ucuc ID -- that...

  • Fading Links Using jQuery:  dwFadingLinks

    UPDATE: The jQuery website was down today which caused some issues with my example. I've made everything local and now the example works. Earlier this week, I posted a MooTools script that faded links to and from a color during the mouseover and mouseout events....

Discussion

    Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!