js实现javaMap对象

<script>
/*js实现map功能*/
function Map()
{
    var struct = function(key, value)
    {
       this.key = key;
       this.value = value;
    }
    var put = function(key, value)
{
       for (var i = 0; i < this.arr.length; i++)
   {
         if ( this.arr[i].key === key )
{
            this.arr[i].value = value;
            return;
         }
       }
       this.arr[this.arr.length] = new struct(key, value);
    }

    var get = function(key)
{
       for (var i = 0; i < this.arr.length; i++)
   {
          if ( this.arr[i].key === key )
  {
            return this.arr[i].value;
          }
       }
       return null;
    }

    var remove = function(key)
{
      var v;
      for (var i = 0; i < this.arr.length; i++)
  {
        v = this.arr.pop();
        if ( v.key === key )
{
           continue;
        }
        this.arr.unshift(v);
      }
    }
  var size = function()
  {
    return this.arr.length;
  }
  var isEmpty = function()
  {
     return this.arr.length <= 0;
  }
  this.arr = new Array();
  this.get = get;
  this.put = put;
  this.remove = remove;
  this.size = size;
  this.isEmpty = isEmpty;
}

</script>

<script>
var map = new Map();
map.put("re","redhacker");
map.put("re","redhacker2");
map.put("do","douguoqiang");
map.put("gq","dougq");
alert("map的大小为：" + map.size())
alert("key为re的map中存储的对象为：" + map.get("re"));
map.remove("re");
alert("移除key为re的对象后，获取key为re的map中存储的对象为：" + map.get("re"));
alert("map移除一个元素后的大小为：" + map.size());
alert("map是否是一个空map:" + map.isEmpty());
</script>