Anyone interested in a regex solution I have put together this function to add/remove/update a querystring parameter. Not supplying a value will remove the parameter, supplying one will add/update the paramter. If no URL is supplied, it will be grabbed from window.location. This solution also takes the url's anchor into consideration.
function UpdateQueryString(key, value, url) {
if (!url) url = window.location.href;
var re = new RegExp("([?&])" + key + "=.*?(&|#|$)(.*)", "gi");
if (re.test(url)) {
if (typeof value !== 'undefined' && value !== null)
return url.replace(re, '$1' + key + "=" + value + '$2$3');
else {
var hash = url.split('#');
url = hash[0].replace(re, '$1$3').replace(/(&|\?)$/, '');
if (typeof hash[1] !== 'undefined' && hash[1] !== null)
url += '#' + hash[1];
return url;
}
}
else {
if (typeof value !== 'undefined' && value !== null) {
var separator = url.indexOf('?') !== -1 ? '&' : '?',
hash = url.split('#');
url = hash[0] + separator + key + '=' + value;
if (typeof hash[1] !== 'undefined' && hash[1] !== null)
url += '#' + hash[1];
return url;
}
else
return url;
}
}
UPDATE
There was a bug when removing the first parameter in the querystring, I have reworked the regex and test to include a fix.
UPDATE 2
@schellmax update to fix situation where hashtag symbol is lost when removing a querystring variable directly before a hashtag