function rollOvers(classString,prefix,parent) {
	// If some or all of the arguements are missing, use defaults.
	var cs = (classString) ? classString : "ro";
	var prefix = (prefix) ? imgPrefix : "_ro";
	var parent = (parent) ? parent : document.body;
	// Get a list of all elements in an array.
	var elements = parent.getElementsByTagName("*");
	// Loop through elements list.
	for(var i=0;i<elements.length;i++) {
		// If the element has a class defined, check if it's a candidate.
		if(elements[i].className) {
			// Clean up class definition(s) string
			var str = elements[i].className;
			str = str.replace(new RegExp("^([\\s]+)|([\\s]+)$", "gm"), "");
			// Put class definition(s) into an array.
			var classes = str.split(" ");
			// Loop through 'classes' array and check for the target class.
			for(var j=0;j<classes.length;j++) {
				if(classes[j]==cs) {
					switch(elements[i].tagName.toUpperCase()) {
						case "A":
							var imgs = elements[i].getElementsByTagName("IMG");
							var img = imgs[0];
							this.setSrc(img,prefix);
							break;
						case "IMG":
							this.setSrc(elements[i],prefix);
							break;
						case "INPUT":
							if(elements[i].type.toUpperCase() == "IMAGE")
								this.setSrc(elements[i],prefix);
							if(elements[i].type.toUpperCase() == "SUBMIT")
								// do nothing
							break;
					}
					break;
				}
			}
		}
	}
}
rollOvers.prototype.setSrc = function(obj,prefix) {
	obj.onmouseover = function() {
		var tmp = this.src.split("/");
		var file =tmp[tmp.length-1];
		var tmp2 = file.split(".");
		tmp2[0] += prefix;
		file = tmp2.join(".");
		tmp[tmp.length-1] = file;
		this.src = tmp.join("/");
	},
	obj.onmouseout = function() {
		var tmp = this.src.split("/");
		var file =tmp[tmp.length-1];
		var tmp2 = file.split(".");
		tmp2[0] = tmp2[0].replace(prefix,"");
		file = tmp2.join(".");
		tmp[tmp.length-1] = file;
		this.src = tmp.join("/");
	}
}