function replaceParamVal(oldUrl, paramName, replaceWith) {
    var re = eval(‘/(‘ + paramName + ‘=)([^&]*)/gi’);
    var nUrl = oldUrl.replace(re, paramName + ‘=’ + replaceWith);
    return nUrl;
}
function hasParameter(name){
    var reg = new RegExp(“(^|&)” + name + “=([^&]*)(&|$)”);
    var r = window.location.search.substr(1).match(reg);
    if (r != null) return unescape(r[2]);
        return null;
}