Hello 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";
                                        $(this).attr("src", src);
                                .mouseout(function() {
                                        var src = $(this).attr("src").replace("_silly", "");
                                        $(this).attr("src", src);

the regular expression should match something like
http://www.examplesite.com/sites/all/files/John.jpg?161717717 (the random numbers at the end are just some added junk drupal throws on for some reason)
and then when you hover over the image it should be
and then return to the original src when you mouseout.
and change it to

Am wondering, wouldn't it be easier to match .jpg (optionally followed by a question mark and some chars) and replace it with _silly.jpg (and any other filetype you use) ?

var src = $(this).attr("src");
src = src.replace(/^(.*)(\.jpg)(\?.*)?$/mg, "$1_silly$2$3");

Yea I am not that great with regex or jquery so I am open to any suggestions, Right now I am busy but will post on here when I find out if that solution works.

That doesnt seem to match anything when I run the page it doesnt change the src when I rollover and in notepad++ the expression doesnt match anything when I set the find to regex.

To remove _whatever the expression is

src = src.replace(/^(.+)(_[^.]+)(.+)$/, "$1$3");

To insert _whatever the expression is

src = src.replace(/^(.+)(\.[^.]+\?.+)$/, "$1_whatever$2");