获取url参数

function getParam(paramName) { 

    paramValue = "", isFound = !1; 

    if (this.location.search.indexOf("?") == 0 && this.location.search.indexOf("=") > 1) { 

        arrSource = unescape(this.location.search).substring(1, this.location.search.length).split("&"), i = 0; 

        while (i < arrSource.length && !isFound) arrSource[i].indexOf("=") > 0 && arrSource[i].split("=")[0].toLowerCase() == paramName.toLowerCase() && (paramValue = arrSource[i].split("=")[1], isFound = !0), i++ 

    } 

    return paramValue == "" && (paramValue = null), paramValue 

}