function Map(){    
	this.container = new Object();    
}    

Map.prototype.put = function(key, value){    
	this.container[key] = value;    
}    
  
Map.prototype.get = function(key){    
	return this.container[key];    
}    
  
Map.prototype.keySet = function() {    
	var keyset = new Array();    
	var count = 0;    
	for (var key in this.container) {    
		// Ìø¹ýobjectµÄextendº¯Êý    
		if (key == 'extend')    
			continue;    
		keyset[count] = key;    
		count++;    
	}    
	return keyset;    
}    

Map.prototype.size = function() {    
	var count = 0;    
	for (var key in this.container) {
		if (key == 'extend')    
		continue;    
		count++;    
	}    
	return count;    
}    

Map.prototype.toString = function(){    
	var str = "";    
	for (var i = 0, keys = this.keySet(), len = keys.length; i < len; i++) {    
		str = str + keys[i] + "=" + this.container[keys[i]] + ";\n";    
	}    
	return str;    
}