Javascript in workflow

System

I am trying to put javascript in the wft (workflow file) in order to get a pop up confirmation alert message for one of the check box. It's giving me an javascript error. Does anybody know where should I put it exactly in my code. (within the <template_script> code or outside)
Here is my javascript code.

<script language="javascript">
function confirm_entry(){
input_box=confirm("Are you sure you want to send it.\n Click OK or Cancel to Continue");
if (input_box==true)
{
alert ("You have clicked ok");
}
else
{
alert ("You clicked cancel");
}}
</script>

Thanks