javascript 实现高效的字符串拼接 高效java中的StringBuffer

function StringBuffer() {    this.buffer = [];  }  StringBuffer.prototype.append = function append(string) {    this.buffer.push(string);    return this;  };  StringBuffer.prototype.toString = function toString() {    return this.buffer.join("");  }; 

 var buf = new StringBuffer(); buf.append("hello"); buf.append("world"); alert(buf.toString());