解决IE7与IE8中JavaScript trim函数缺失的自定义实现

自定义trim函数实现代码示例

<html> 
 <head> 
  <title>test</title> 
  <script type="text/javascript"> 
    String.prototype.trim = function() 
    { 
      return this.replace(/(^\s*)|(\s*$)/g, ""); 
    } 
     
    function check(){ 
      var str = document.getElementById("test").value; 
       
      alert(str.trim()); 
    } 
  </script> 
 </head> 
  
 <body> 
  <center> 
    <input id="test" type="text" /> 
    <input id="but" type="button" value="检验" onclick="check();"/> 
  </center> 
 </body> 
</html>