вставка параметра в url

helper.js

function insertParam(key, value, search)
{
    key = encodeURI(key); value = encodeURI(value);

    search = search.toString();

    if(search=='')
        search = document.location.search;

    if(search[0]=="?")
        search = search.substr(1);

    var kvp = [];
    if(search.search("&")==-1 && search!='')
        kvp = [search];
    else if(search=='')
        kvp = [];
    else
        kvp = search.split('&');

    var i=kvp.length;
    var x;

    while(i--)
    {
        x = kvp[i].split('=');

        if (x[0]==key)
        {
            x[1] = value;
            kvp[i] = x.join('=');
            break;
        }
    }

    if(i<0) {kvp[kvp.length] = [key,value].join('=');}

    return kvp.join('&');

}