Remove everything after a certain character

You can also use the split() function. This seems to be the easiest one that comes to my mind :).

url.split('?')[0]

jsFiddle Demo

One advantage is this method will work even if there is no ? in the string - it will return the whole string.

var s = '/Controller/Action?id=11112&value=4444';
s = s.substring(0, s.indexOf('?'));
document.write(s);

Sample here

I should also mention that native string functions are much faster than regular expressions, which should only really be used when necessary (this isn't one of those cases).

Updated code to account for no '?':

var s = '/Controller/Action';
var n = s.indexOf('?');
s = s.substring(0, n != -1 ? n : s.length);
document.write(s);

Sample here

var href = "/Controller/Action?id=11112&value=4444";
href = href.replace(/\?.*/,'');
href ; //# => /Controller/Action

This will work if it finds a '?' and if it doesn't