url后的参数转json对象

var url = window.location.href;

var str = getParam(url);
var str = JSON.parse(str);
var userId = str[0].userId;

function getParam(url)
        {
            var index = url.indexOf("&") //获取？字符位置
            url = url.substr(index+1); //截取url参数部分
            var arr = new Array();
            arr = url.split('&'); //将各参数分离
            var str = '[{';
            //将参数数组部分转换为JSON数据
            for(var i=0;i<arr.length;i++)
            {
                var index1 = arr[i].indexOf('=');
                //判断最后一个参数是否有值
                if(index1 == -1)
                {
                    str+=',"'+arr[i]+'":""';
                    continue;
                }
                var key = arr[i].substr(0,index1);
                var val = arr[i].substr(index1+1);
                var str1= ',';
                if(i==0)
                {
                    str1 = '';
                }
                str+=str1+'\"'+key+'\":'+'\"'+val+'\"';
            }

            return str+'}]';
        }