function GetQueryVariable(variable) 
{
    var query = window.location.search.substring(1);
    var vars = query.split("&");
    for (var i=0;i<vars.length;i++) 
    {
        var pair = vars[i].split("=");
        if (pair[0] == variable)
        {
            return pair[1];
        }
    } 
    return null;
}