js防止表单重复提交

<script language="javascript">   

    var checkSubmitFlg = false;   

    function checkSubmit() {     

        if (!checkSubmitFlg) { 

        checkSubmitFlg = true;     

        return true;  

        }else{

         alert("不能重复提交");

         return false;

        }

     }

</script>



<form action="XXXX" method="POST"   onsubmit="return     checkSubmit()">

  内容:<input type="text" name="content" value=""/><br>

  <input type="submit" value="提交"><br>

</form>