用javascript实现用户登录验证

 <script language=javascript>
 function checkSubmit()
 {
     if ((document.form1.name.value)=="")
     {
         window.alert ('姓名必须填写');
         document.form1.name.select();
         document.form1.name.focus();
         return false;
     }
     else
         return true;
 }
 </script>
 <form name=”form1″ onsubmit=”javascript:return checkSubmit()”>
 <input type=”text” name=”name”>
 </form>