ASP.net button onserverclick only works when onclick isn't defined

    protected void btnNext_Click(object sender, EventArgs e)
    {
        btnNext.InnerHtml = "CLICK";
    }

    <button type="submit" runat="server" onserverclick="btnNext_Click" id="btnNext">Next &gt;</button>

This works fine, but when I add an onclick event:

<button type="submit" runat="server" onserverclick="btnNext_Click" on开发者_如何学Cclick="return checkForm();" id="btnNext">Next &gt;</button>

And in the head:

<script type="text/javascript">

    function checkForm() {

        if (document.getElementById("<%=lstChooseSpec.ClientID %>").value) {
            return true;
        } else {
            $.jGrowl("<strong>Warning!</strong><br />Please select an item", { sticky: true });
            return false;
        }
    }
</script>

It submits the form, but doesn't change the buttons text to 'CLICK'. The text only changes to 'CLICK' when the onclick() isn't defined, although the form is still submitting!

try without 'return': <button type="submit" runat="server" onserverclick="btnNext_Click" onclick="checkForm();" id="btnNext">Next &gt;</button>
Or if you wanted checkForm() to control whether to post or not - do like this:

onclick="if (!checkForm()) return;"

The reason you're seeing this is because when you have both on a button it runs your on click handler followed by the __doPostBack function so the onclick would look something like this

onclick="return checkForm(); __doPostBack('btnNext','')

So as you can see the __doPostBack, which actually sets up which server function to call, is never called. However, since the button is of type submit, the form is still sent back to the server.

Try this:

onclick="javascript:if (!validaForm()) return false;"

It worked for me.

Can you try with LinkButton:

<asp:LinkButton type="submit" runat="server" onserverclick="btnNext_Click" onclick="return checkForm();" id="btnNext">Next &gt;</asp:LinkButton>

Front End

  <button  id="submit1" runat="server"  
              onclick="if(confirm('Sure?')) { } else{ return false} ;"                       onserverclick="submit_ServerClick"  >save</button>

Back End

 protected void submit_ServerClick(object sender, EventArgs e)
 {
 }