var   regu   =   "^(你要查的字符)"      
   var   re   =   new   RegExp(regu);      
    if   (要查找的字符串.search(re)   !=   -1)       
    {      
          alert('查到了');      
    }      
    else      
    {    
           alert('没查到！');    
     } 

?