function StringBuffer() {   this.__strings__ = []; }; StringBuffer.prototype.Append = function (str) {   this.__strings__.push(str);   return this; }; //格式化字符串 StringBuffer.prototype.AppendFormat = function (str) {   for (var i = 1; i < arguments.length; i++) {     var parent = "//{" + (i - 1) + "//}";     var reg = new RegExp(parent, "g")     str = str.replace(reg, arguments[i]);   }    this.__strings__.push(str);   return this; } StringBuffer.prototype.ToString = function () {   return this.__strings__.join(''); }; StringBuffer.prototype.clear = function () {   this.__strings__ = []; } StringBuffer.prototype.size = function () {   return this.__strings__.length; }

var sbHtml=new StringBuffer(); sbHtml.Append('hello'); sbHtml.Append('world');    console.log(sbHtml.ToString());