Enter Key Default Submit Button

If there is only one button in a WEB FORM, pressing ENTER will enable the default submit button.

If there are more than one buttons in a web form, then we can define the default submit thru DEFAULTBUTTON property either in the FORM  or with an PANEL.

1<form defaultbutton="btnSubmit" id="form1" runat="server"
</form >

2) <panel defaultutton="btnSubmit" id="pnlFirst" runat="server"></panel>