<script type="text/javascript"> function StringBuffer() { this._strings = new Array(); } StringBuffer.prototype.append = function(str) { this._strings.push(str); //StringBuffer.prototype.length = this._strings.length;//每多一行，就会多消耗处理时间 var i = "asdfasdf"; } StringBuffer.prototype.toString = function() { this._strings.join(""); } /*String类 + 号累加*/ var d = new Date();//累加开始时间 var str = "1"; for (var i = 0; i < 200; i++) { str += "ssss"; for (var i = 0; i < 30000; i++) { str += "text"; } } var d2 = new Date(); //累加结束时间 document.write("+："+(d2.getTime() - d.getTime()) + "milliseconds");//累加30000用时 /*自定义StringBuffer类 字符串累加*/ d = new Date(); //StringBuffer开始时间 var buffer = new StringBuffer(); for (var i = 0; i < 200; i++) { str += "ssss"; for (var i = 0; i < 30000; i++) { buffer.append("text"); } } var resultstr = buffer.toString(); d2 = new Date(); document.write("<br/>StringBuffer：" + (d2.getTime() - d.getTime()) + "milliseconds"); /*直接使用Array 不进行封装*/ d = new Date(); var arr = new Array(); for (var i = 0; i < 200; i++) { str += "ssss"; for (var i = 0; i < 30000; i++) { arr.push("text"); } } var resStr = arr.join(""); d2 = new Date(); document.write("<br/>Array：" + (d2.getTime() - d.getTime()) + "milliseconds"); </script> [code]