javascript StringBuilder类实现

// Initializes a new instance of the StringBuilder class 
// and appends the given value if supplied 
function StringBuilder(value) 
{ 
this.strings = new Array(""); 
this.append(value); 
} 
// Appends the given value to the end of this instance. 
StringBuilder.prototype.append = function (value) 
{ 
if (value) 
{ 
this.strings.push(value); 
} 
} // Clears the string buffer 
StringBuilder.prototype.clear = function () 
{ 
this.strings.length = 1; 
} 
// Converts this instance to a String. 
StringBuilder.prototype.toString = function () 
{ 
return this.strings.join(""); 
}

代码看上去很简单直接。实际上就是用array,push,join等来实现，以下是如何使用该类

// create a StringBuilder 
var sb = new StringBuilder(); 
// append some text 
sb.append("Some of those preparing for international "); 
sb.append("exams such as the TOEFL "); 
sb.append("need extra practice for the listening section"); 
// get the full string value 
var s = sb.toString(); 
alert(s);

非常简单，不需要太多的说明。如果你在.NET中用了StringBuilder，你也会知道这里如何用。