Question

Possible Duplicate:
Get query string values in JavaScript

I “had” this pattern but it didn’t quite give me what I need, though it worked.

var regex = new RegExp('\\b' + data.keyword + '(=[^&]*)?(&|$)',"gi");

But the following regular expressions “is” what I need but i can’t seem to get it to work within the regex obj:
/&dyanmicTxtHere(\=[^&])?(?=&|$)|^dyanmicTxtHere(\=[^&])?(&|$)/

I tried: This is NOT working –

var regex = new RegExp('&' + data.keyword + '(=[^&]*)?|^' + data.keyword + '(=[^&]*)?&?',"gi");

I can’t figure out why. So the above regex should strip out my passed param (and vlaue)(data.keyword), and deal with the ? and & wherever that param sits in the url. It

So, what would this match?

http://www.someurl.com?Keyword=foo

http://www.someurl.com?up=down&Keyword=foo

http://www.somurl.com?up=down&keyword=foo&left=right

etc… so, if I passed in “Keyword” as my dynamic param, then it would remove it and its associated value.

Answer 1

Obviously what follows is not a regular expression; but it should, I think, fulfil your requirements. It takes advantage of the requirements of name-value pairs in a GET query-string, and uses simple string, and some array, manipulation to examine the various (if any) name-value pairs from the passed URL:

function removeParam(url, param) {
    // checks for the existence of a '?' in the passed url:
    var queryAt = url.indexOf('?') + 1;
    /* function exits if:
       1. no 'url' parameter was passed,
       2. no 'param' parameter was passed in, or
       3. the 'queryAt' variable is false, or has a falsey value */
    if ((!url || !param) || !queryAt) {
        return false;
    }
    else {
        /* if the 'param' passed in wasn't found in the 'url' variable,
           the function exits, returning the original url (as no modification
           is required */
        if (url.indexOf(param) == -1) {
            return url;
        }
        else {
                /* gets the substring of the url from the first
                   character *after* the '?' */
            var all = url.substring(queryAt),
                // creates an array of the name and value pairs
                nameValues = all.split('&'),
                // creating a new array
                newNameValues = [],
                parts;
            // iterates through each name-value pair
            for (var i = 0, len = nameValues.length; i < len; i++) {
                // splits the name-value pair into two parts
                parts = nameValues[i].split('=');
                /* if the first part (the 'name' of the param) does not
                   matches what you're looking for then the whole name-value
                   pair is pushed into the 'newNameValues' array */
                if (parts[0] !== param) {
                    newNameValues.push(nameValues[i]);
                }
            }
            // returns the reconstructed URL
            return url.substring(0, queryAt) + newNameValues.join('&');
        }
    }
}

JS Fiddle demo.