HtmlEncode

String.prototype.toHtmlEncode   =   function() {   
  var str = this;   
  str=str.replace("&","&");   
  str=str.replace("<","&lt;");   
  str=str.replace(">","&gt;");   
  str=str.replace("'","&apos;");   
  str=str.replace(""","&quot;");   
  return str;   
  }   

用法

"".toHtmlEncode()