Question

I am facing a problem with buttons.

I want a client side validation to occur(say selecting a maximum of only 4 checkboxes in a datalist).

I used a INPUT TYPE=”BUTTON” RUNAT=”SERVER” style of tag. and put Onserverclick=”someservermethod” which works fine.

I wrote a Validate() and added onclick=”return validate();” to the above HTML markup and was thinking if it returns false then my server side code someservermethod() would not execute and it works great as expected

But when I return true I thought it would fire my someservermethod(), but it is not working. Any thoughts on why it is not working?

HTML MARKUP BELOW FOR THE BUTTON

button onclick="return ValidateSelection();" type="button" id="btnSubmit"
                runat="server" onserverclick="btnSubmit_Click"

JAVASCRIPT CODE

function ValidateSelection()
{
  if(good)
  {
    // I expect that my server side code btn_Submit would have got called. But
    // it doesn't get called.
    return true;
  }
  else
  {
    //This works great. Not calling the server side method for the button
    alert('something happened');
    return false;
  }  
}

I think I am messing up with the formatting. Pardon me.

Answer 1

The control you are using right now it HtmlButton which is not “fit” for what you are trying to do, as your onclick overwrites the required client side code for the post back.

What you need is the Button control which does support overwriting the client side onclick and still perform the post back as usual.

Change the markup to this and it should work:

<asp:button OnClientClick="return ValidateSelection();" id="btnSubmit" runat="server" OnClick="btnSubmit_Click" Text="Submit"></asp:Button>