codice:
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script language="javascript" type="text/javascript">
<!--
function Text1_onchange()
{
var v = document.getElementById("TextBox1").value.replace(/\,/g, ".");
v = parseFloat(v);
if(!isNaN(v))
document.getElementById("TextBox2").value = v * 200.0;
else
alert("TextBox1 non numerico");
}
// -->
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:TextBox ID="TextBox1" runat="server" onchange="return Text1_onchange()"></asp:TextBox>
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
</div>
</form>
</body>
</html>