Question

I want to replace the src attribute for all images matching a regex using Greasemonkey scripting.
Example:

Replace http://aff.kooora.com/i/z3.gif

With http://example.com/aff.kooora.com/i/z3.gif

I have no experience in scripting but this is what I came up with:

var allImg=document.getElementsByTagName("img"), i=0, img;
var pattern = aff\.kooora\.com/([A-Za-z0-9/._]*);
while(img=allImg[i++])
{
    result = pattern.exec(img);
    if (result!=null) 
        img.src=img.src.replace(result, 'http://example.com/' + result);
}

It doesn’t work.

Answer 1

Your regular expression is the problem, you need to wrap it in slashes (otherwise the interpreter has no clue that it should treat that as a regexp):

var allImg=document.getElementsByTagName("img"), i=0, img;

var pattern = /^http\:\/\/aff\.kooora\.com\/(.*)$/;

while (img = allImg[i++])
{
    if (img.src.match(pattern)) {
        img.src = img.src.replace(pattern, 'http://example.com/aff.kooora.com/$1');
    }
}