关于哈希表存值、取值、遍历、长度判断在js中的用法

var map = {}; // Map map = new HashMap();新建map对象
map[key] = value; // map.put(key, value);存值
var value = map[key]; // Object value = map.get(key);取值
var contain = key in map; // boolean has = map.containsKey(key);boolean返回是否存在
delete map[key]; // map.remove(key);删除
// 遍历  
for(key in map){  
    alert(key + map[key]);  
}  
//长度判断
var length  = Object.keys(map).length ;