js______StringBuffer()方法

function StringBuffer(){
this._strings_ = new Array();
}
StringBuffer.prototype.append = function(str){
this._strings_.push(str);
};
StringBuffer.prototype.toString = function(){
return this._strings_.join("");
}
 
 var buffer = new StringBuffer();
for(var i=0;i<4;i++)
{buffer.append('<b>abc</b>');}

buffer.append('cde');
var str = buffer.toString();