JS表单验证

<script language="javascript" type="text/javascript">

        function checkSubmit()

        {

            if (document.form1.jtitle.value=="")

            {

              alert("对不起，请输入标题！");

              document.form1.jtitle.focus();

              return false;

             }

        }

</script>

 

<form id="form1" onsubmit="javascript:return checkSubmit();" >

   <input type="text" name="jname"/>

   <input type="submit" name="submit"/>

</form>