javascript calculation formula is not working
<p>I have folowing javscript fucntion to make some claculation with textboxes bu when i call this function on textbox the it does'nt works.Here is my JS code</p>

<p><strong>Update</strong> </p>

<pre><code>&lt;script type="text/javascript" language=javascript&gt;
function calc()
{
var pkrusd;
var pkrusd = parseFloat(document.getElementById("&lt;%=txtpkrusd.ClientID %&gt;").value, 10); 
var ratelb;
ratelb = parseFloat(document.getElementById("&lt;%=txtRatelb .ClientID %&gt;").value, 10); 
var res;
res = parseFloat(document.getElementById("&lt;%=txtF5.ClientID %&gt;").value, 10); 
res=pkrusd*ratelb;
}
&lt;/script&gt;

&lt;asp:TextBox ID="txtpkrusd" runat="server" BackColor="Yellow" style="text-align:right" onkeyup="calc()"&gt;&lt;/asp:TextBox&gt;
    &lt;asp:TextBox ID="txtRatelb" runat="server" BackColor="Yellow" Style="text-align: right" onkeyup="calc()"&gt;&lt;/asp:TextBox&gt;
</code></pre>

<p>Please any one help me to find that what exactly i am missin in the code.</p>
