js获取url参数值

    
function getRequestParameter(name) {
        var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
        var r = window.location.search.substr(1).match(reg); //获取url中"?"符后的字符串并正则匹配
        var context = "";
        if (r != null)
            context = r[2];
        reg = null;
        r = null;
        return context == null || context == "" || context == "undefined" ? "" : context;
    }