Get URL Parameters Using Javascript

Get URL Parameters Using Javascript

An easy way to parse the query string in your URL to grab certain values.

Source: http://www.netlobo.com/url_query_string_javascript.htmlexpressions. Here is the function:

function gup( name )
{
name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
var regexS = "[\\?&]"+name+"=([^&#]*)";
var regex = new RegExp( regexS );
var results = regex.exec( window.location.href );
if( results == null )
return "";
else
return results[1];
}

The way that the function is used is fairly simple. Let's say you have the following URL:
http://www.foo.com/index.html?bob=123&frank=321&tom=213#top
You want to get the value from the frank parameter so you call the javascript function as follows:

var frank_param = gup( 'frank' );

Now if you look at the frank_param variable it contains the number 321. The query string was parsed by the regular expression and the value of the frank parameter was retrieved. The function is smart in a couple of ways. For example, if you have an anchor in your URL like our example URL above does (#top) the gup() function knows to stop before the # character. Also, if a requested parameter doesn't exist in the query string then an empty string is returned instead of a null.