Jquery :: Regex - Replace The Src Of An Image When The User Hovers Over It

I am writing a script that will replace the src of an image when the user hovers over it. I am using jquery and regex to accomplish this and have tested it on my local server but the src of the images on the live server is different and uses a non-relative path.
Here is my code

$(document).ready(function() {
$("img.imagefield").mouseover(function() {
var regex = "^(http|https|ftp)://[a-zA-Z0-9-.]+.[a-zA-Z]{2,3}(:[a-zA-Z0-9]*)?/sites/all/files/[a-zA-Z]*";
var src = $(this).attr("src").match(regex) + "_silly";
[Code]...