55 search处理

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            /*
                封装函数解析search

                ?id=5&search=ok

                获取url中search，通过传入对应key，返回key对应的value

                例子：传入id，返回5
            */
           function getvalue(search, key){
                //<1>找出key第一次出现的位置
                var star = search.indexOf(key)
                if(star == -1){
                    return
                }else{
                    //<2>找出键值对结束的位置
                    var end = search.indexOf("&", star)
                    if(end == -1){
                        //这是最后一个键值对
                        end = search.length;
                    }
                }

                //<3>将键值对提取出来
                var str = search.substring(star, end)
                //alert(str)
                //<4>key=value  获取value
                var arr = str.split("=")
                return arr[1]
           }

           var apple = "?id=5&search=ok"
           alert(getvalue(apple, "search"))
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