原生态的js map

<script>var map = {}; map["key1"] = "Value1"; // 加入值对 map["key2"] = "Value2"; map["key3"] = "Value3"; for(var k in map) { // 遍历   alert(k + " = " + map[k]); } var mykey="key1";alert("key1的数值"+map[mykey] );delete map["key1"]; // 删除var mykey="key5";if(mykey in map){//判断是否存在alert(mykey+"的数值"+map[mykey] );}else{alert("不存在"+mykey+"的数值");}</script>