js 之 StringBuffer 工具类

function StringBuffer(){
	this._strings = new Array();
}

StringBuffer.prototype.append = function(str){
	this._strings.push(str);
	return this;
}

StringBuffer.prototype.toString = function(){
	return this._strings.join("");
}


StringBuffer.prototype.length = function(){
	var str = this._strings.join("");
	return str.length;
}