"On exit: Pass field value to next page" + When null (JS)

[Goodwin]

I'm trying to complete a simple Javascript code whereby I test whether a passed parameter is null. However, whenever a value is not supplied by the user, my code doesn't return anything. Here's what I have so far ([@Book] is the Caspio parameter name):

var BookNumber;

if ([@Book]==null)

{

BookNumber = "All";

}

else

{

BookNumber = [@Book];

}

document.write(BookNumber);

If [@Book] has a value, the code works as expected. If it doesn't have a value, the code doesn't work. Any help would be greatly appreciated. By the way, I tried testing for undefined and empty string (""), neither of which helped.

[skywalker]

You could try this. I havent tested it but might help...

var BookNumber: = "[@Book]";

if (BookNumber == (""))  {

BookNumber = "All";
}

else  {

Your code....
}

[Goodwin]

Thanks for the reply. I gave it a shot, but it didn't help. Any other ideas?

[bahar_vm]

How about this:

<script>
var BookNumber = "[@Book]";

if (BookNumber == "")  {

BookNumber = "All";
}
document.write(BookNumber);
</script>

Also where is [@Book] coming from? And which kind of DataPage you have this code in? For example if you are in update form, details or results page you can read the value of a field using the following parameter: [@field:FIELDNAME]. If this is a parameter you are passing from another web page and receiving in the Caspio DataPage using this name: [@Book] then it is fine.

I hope this helps.

Best,

Bahar M.