请教用正则表达式去除数字和Xx外的字符
var   sdf   =    "      2345234523 "; 
 var   re   =   new   RegExp( "[^0-9xX] ", " "); 
 sSFZH   =   re.exec(sdf   );	   
 这么写出错 
 请教正确方法
------解决方案--------------------用replace   
  <script language= "javascript ">  
 	var sdf =  "  2345234523 "; 
 	re = /[^0-9xX]/g; 
 	sSFZH = sdf.replace(re,  " "); 
 	alert(sSFZH); 
  </script>