/*
Function: imgMouseOverEvents
		handles hover states for images. Producers simply author all their 
		images to have an on version and an off version with same naming 
		conventions, then call this function with those conventions and 
		a css selector. All images that match that selector will get the 
		mouseover behavior applied to them automatically.

Example:
		(start code)
		<img src="myimg_off.gif" class="autoMouseOver">
		assuming that my hover image is the same path with _off
		   substituted with _on; so: myimg_on.gif is the hover version
		<script>
			imgMouseOverEvents('_off', '_on', 'img.autoMouseOver');
		</script>
		(end)
		You can call this function as soon as the DOM is ready.
		
		Note:
		The default instance of this function is included in this library.
		If producers name their on/off state files with "_on" and "_off"
		in the file names and give their images the class "autoMouseOver"
		then they don't have to write any javascript. This also works for
		inputs.
		
		Automatically executed versions:
		img.autoMouseOverOff - swaps '_off' for '_over'
		img.autoMouseOver - swaps '_off' for '_on'
		input.autoMouseOver - swaps '_off' for '_on'
		
		Arguments:
		outString - the string to substitute for the on string when the user mouses out
		overString - the string to substitute for the out string when the users mouses over
		selector - css selector to apply this behaviour
		
		See Also: <tabMouseOvers>
	*/
function imgMouseOverEvents(outString, overString, selector) {
	$$(selector).each(function(image) {
		image = $(image);
		if ($type(image.src)) {
			if (image.src.indexOf(outString) > 0) {
				image.addEvent('mouseover',function(){
					image.src = image.src.replace(outString, overString);
				}).addEvent('mouseout', function(){ 
					image.src = image.src.replace(overString, outString);
				});
			}
		}
	});
};
window.onDomReady(function(){imgMouseOverEvents('_off', '_over', 'img.autoMouseOverOff, input.autoMouseOver');});
window.onDomReady(function(){imgMouseOverEvents('_off', '_on', 'img.autoMouseOver');});