you can validate in client side using javascript or jQuery
<input type="text" id="a" value="0" />
<input type="text" id="b" value="0"/>
<input type="text" id="c" önkeyup="calc()" value="0"/>
<input type="text" id="d" value="0"/>
function calc() {
document.getElementById('d').value = parseInt(document.getElementById('c').value) * parseInt(document.getElementById('b').value);
if (document.getElementById('a').value == document.getElementById('d').value) {
alert("matching values");
}
}
Demo[
^]
if you need to do it with
asp:TextBox
<asp:TextBox ID="a" runat="server" ClientIDMode="Static"></asp:TextBox> <asp:TextBox ID="b" runat="server" ClientIDMode="Static"></asp:TextBox>
<asp:TextBox ID="c" runat="server" onchange="javascript:calc();" ClientIDMode="Static">/asp:TextBox>
<asp:TextBox ID="d" runat="server" ClientIDMode="Static"></asp:TextBox>