js 正则非字母和数字一律替换成下划线

<script language="javascript"><!-- var str="Trouble with IP address conflict. Help needed.? "; str=str.replace(/[^/d/w]+$/,""); str=str.replace(/[^/d/w]/g,"_"); alert(str); // --></script>

 

<script   language="javascript">  
        var   str="Trouble   with   IP   address   conflict.   Help   needed.?   ";  
        str=str.replace(/[^/d/w]+$/,"");  
        str=str.replace(/[^/d/w]/g,"_");  
        alert(str);  
  </script>