var Rollover = function () {};

Rollover.suffix = '_over';
Rollover.preloadimages = [];
Rollover.overflag = [];

Rollover.overimage = function (obj) {
	if (obj.src && obj.src.indexOf('.') != -1) {
		obj.src = Rollover.getrolloverimagefile(obj.src);
		this.overflag.push(obj);
	}
}
	
Rollover.normalimage = function (obj) {
	var flag = false;
	for (var i in this.overflag) {
		if (this.overflag[i] == obj) {
			flag = true;
			this.overflag[i] = null;
			break;
		}
	}
	if (flag && obj.src && obj.src.indexOf('.') != -1) {
		obj.src = Rollover.getoriginalimagefile(obj.src);
	}
}
	
Rollover.getrolloverimagefile = function (path) {
	var filename = path.substring(0, path.lastIndexOf('.'));
	var extention = path.substring(path.lastIndexOf('.'), path.length);
	return filename + Rollover.suffix + extention;
}
	
Rollover.getoriginalimagefile = function (path) {
	var filename = path.substring(0, path.lastIndexOf('.')-Rollover.suffix.length);
	var extention = path.substring(path.lastIndexOf('.'), path.length);
	return filename + extention;
}

Rollover.initrolloverimages = function() {
	var images = document.getElementsByTagName('img');
	for (var i=0; i<images.length; i++) {
		var classValue = null;
		if (images[i].getAttribute('className'))
			classValue = images[i].getAttribute('className');
		else if (images[i].getAttribute('class'))
			classValue = images[i].getAttribute('class');
		if (classValue != null && classValue.indexOf('rollover') != -1 && images[i].src) {
			images[i].onmouseover = function() {
				Rollover.overimage(this);
			};
			images[i].onmouseout = function() {
				Rollover.normalimage(this);
			};
			Rollover.preloadimages[i] = new Image();
			Rollover.preloadimages[i].src = Rollover.getrolloverimagefile(images[i].src);
		}
	}
};


function addLoadEvent(func) {
	var old_onload = window.onload;
	if (typeof window.onload != 'function') {
    	window.onload = func;
	} else {
		window.onload = function() {
			old_onload();
			func();
		}
	}
}

addLoadEvent(Rollover.initrolloverimages);