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" onclick="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!

Answers:

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Method 1

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;"

Method 2

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.

Method 3

Try this:

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

It worked for me.

Method 4

Can you try with LinkButton:

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

Method 5

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)
 {
 }

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0