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Degradable SELECT onChange

Whenever I go to Google Analytics I notice a slight flicker in the dropdown list area. I see a button appear for the shortest amount of time and the poof! Gone. What that tells me is that Google is making their site function whether the user has JavaScript or not. The following is a quick explanation of how it works.

The XHTML

<iframe id="site-frame" src="http://<?php echo $_POST['site'] ? $_POST['site'] : 'scriptandstyle.com'; ?>" style="border:1px solid #ccc;float:right;width:700px;height:500px;"></iframe>

<form action="" method="post">
	<select name="site" id="site">
		<option value="">Select a Site</option>
		<option value="github.com/darkwing">GitHub</option>
		<option value="mootools.net">MooTools</option>
		<option value="scriptandstyle.com">Script & Style</option>
		<option value="twitter.com/davidwalshblog">Twitter</option>
	</select>
	<input type="submit" value="Go" class="button" id="submit-button" />
</form>

My example is a dropdown list that manipulates an iFrame. Note that we use a form tag and submit button so that the site functions well without JavaScript.

The JavaScript

//when the window has loaded...
window.onload = function() {
	//hide the button 
	document.getElementById('submit-button').style.display = 'none';
	//our event function
	var handler = function() {
		if(select.value) {
			document.getElementById('site-frame').src = 'http://' + select.value;
		}
	};
	//add the event listener
	var select = document.getElementById('site');
	if(select.addEventListener){
		select.addEventListener('change',handler,false);
	}
	else {
		select.attachEvent('onchange',handler,false);
	}
};

When the window loads, we hide the submit button and add the event listener. If the user doesn't have JavaScript, all of our JavaScript gets ignored. Simple.

This system is very easy to implement and well worth the effort to make your website more accessible.

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