/**
 * Utilities
 * utilities for common web site.
 *
 * 1. RollOverImage
 */


/**
 * RollOverImage
 * 
 */
var RollOverImage = new Class({
	
	/**
	 * selector
	 */
	selector: null,
	
	/**
	 * hover image postfix
	 */
	postfix: '_over',
	
	/**
	 * constructor
	 * pass a selector of rollover image.
	 */
	initialize: function(selector){
		if (!selector) {
			selector = 'img.rollover';
		}
		var self = this;
		$$(selector).each(function(img){
			img.addEvent('mouseenter', function(event){
				if (!img.retrieve('hoverImageSrc') && img.src.indexOf(self.postfix)==-1) {
					var pos = img.src.lastIndexOf('.');
					img.store('originalImageSrc', img.src);
					img.store('hoverImageSrc', img.src.substr(0, pos)+self.postfix+img.src.substr(pos));
				}
				img.src = img.retrieve('hoverImageSrc');
			});
			img.addEvent('mouseout', function(event){
				if (img.retrieve('originalImageSrc')) {
					img.src = img.retrieve('originalImageSrc');
				}
			});
		});
	}
	
});