JavaScript - Extracting variable from string

I have the following code which works awesome for getting the variables form the URL:

HTML Code:

---

function $_GET(q,s) {
  s = (s) ? s : window.location.search;
  var re = new RegExp('&'+q+'=([^&]*)','i');
  return (s=s.replace(/^\?/,'&').match(re)) ? s=s[1] : s='';
}

document.getElementById(RefId).value = $_GET('refcode');

---

But it doesn't work if I use document.referrer instead of window.location

If I place window.location into a string and use the string in the function it works. If I place document.referrer in a string and use the string in the function it doesn't work.

The values of window.location is

Code:

---

http://site.org/Default.aspx?refcode=12345&pageId=890916

---

The value of document.referrer is

Code:

---

http://site.org/bluepage.html?refcode=12345

---

Any thoughts?

your regular expression looks for a string starting with an ampersand ("&"), and the second value you posted doesn't contain one. you'll need to modify your regular expression to either make the ampersand optional (something like: '&?', though that could bring up other potential issues), or find a better expression to represent what you need.

I know that you're trying to replace the question mark with an ampersand, but you're only doing that replacement if the first character of the string is a question mark, and the first character of the string is 'h' in both cases.

edit: also, document.referrer.search doesn't return the query string of the referrer like window.location.search does; you'll need to parse out the query string separately. I was assuming before that you were just using window.location and document.referrer, rather than window.location.search and (perhaps?) trying to use document.referrer.search -- I hadn't looked closely enough at that point.