The below code use to add twoo number by the
using of JavaScript only.
<script language="javascript"
type="text/javascript">
function Navigate() {
var x = document.getElementById("txt1").value;
var y = document.getElementById("txt2").value;
var z =parseInt( x )+parseInt( y);
document.getElementById("txt3").value = z;
}
</script>
<body>
<form id="form1"
runat="server">
<div>
<%-- <asp
button type="button" onclick="alert('Welcome!')">Click Me!</button>--%>
<asp:Button
ID="Button1"
UseSubmitBehavior="true"
Text="Open Web site"
OnClientClick="Navigate()"
runat="server"
/>
<asp:TextBox
ID="txt1"
runat="server"></asp:TextBox>
<asp:TextBox
ID="txt2"
runat="server"></asp:TextBox>
<asp:TextBox
ID="txt3"
runat="server"></asp:TextBox>
</div>
</form>