I've the following code in the form Settings/Confirm Options/Redirect to Custom HTML Page; and it is working well,
..............
................
<script type="text/javascript">
// Transfer it
window.location.href = "http://www.marchsoft.com";
</script>

However I want to make this forwarding in a condition, based on a hidden form parameter (Grand_Total) but following code fails; I appreciate your assistance.

<script type="text/javascript">
if (!isNaN("[Grand_Total]"/1)&&(parseInt("[Grand_Total]")>0)){
// Transfer it
window.location.href = "http://www.marchsoft.com";
}
</script>

The form builder users $_SESSION's for the variables to transfer them through to the confirmation. I think you can catch them that way.

I'm not sure if I understand you. The form hidden parameter (Grand_Total) is being populated in the script via syntax [Grand_Total] for instance;
..............
................
<script type="text/javascript">
// Transfer it
window.location.href = "http://www.marchsoft.com?myTotal=[Grand_Total]";
</script>
.........
and; testing the script with hard-coded value also working outside of the Form Builder Confirmation.
<script type="text/javascript">
if (!isNaN("500"/1)&&(parseInt("500")>0)){
// Transfer it
window.location.href = "http://www.marchsoft.com";
}
</script>

But same script is not working in Form_Builder; I was expecting to use Form hidden parameters can use inside of Confirmation Options via [Grand_Total] to make conditional forward. I appreciate if you please elaborate more.

Just clarification;
as far as I understood, the brackets are used to signal you want field data from the form inserted into the confirmation/summary page after the form has been submitted. The brackets are for the HTML page after the form has been submitted (the confirmation/summary page).

Therefore I was expecting HTML page will be evaluated after the value of form-builder hidden data Grand_Total replaced in the page including script.

That's when your using their scripts. What your trying to do is outside the programing of form builder. I usually write my own custom myformname.php to do all the processing. I will often use $_SESSION's to give feed back to the user.

Eric, I didn't get when you say their script!. Who's script?
It is clearly Redirection solution after form is submitted. Area is provided by Form Builder to customize HTML behavior after form submission, which scripting also suggested in this forum to propagate filled data in the form! More than that, FormBuilder has drop box giving option to propoagate Form related Data in brackets. Do I miss anything here or is this is a bug?

I'm saying that it's easier for me to code my own myformname.php script to process the form then to alter any of the existing scripts that the form builder uses. Don't get me wrong the form builder works great but it was built to handle a lot of situations and user needs. There's one thing that you can't deny and that is the form builder builds awesome forms. That being said there's things that the form builder can't do because of many of the things it can do. To get around this for many of my forms I have hand coded the myformname.php that the formname.html submits to. This allows me to do anything I want with the variables. I know the form builder users $_SESSSION's to handle variables. You are correct in that the form builder users variables in the form of [my_variable_name] but I do believe that is only in the beginning so the scripts know what the variables are. All the variables are available in the standard format of $_POST['myvariablename'], if you build your own myformname.php to replace the one the form builder generates. You should be able to set your own $_SESSION variables and carry them through to the confirmation page of your choice. I might have an example some where but I'm not sure I can find it as I found it faster to build my own then to hack the existing.