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Use Custom Missing Image Graphics Using Dojo

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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.

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Discussion

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