The Error Message pane below appears the middle of the Script Object window when you add a Script Object to a page.
If the message in the Error Message pane reads Expression OK then your script does not contain any syntax errors, such as a missing curly bracket or a missing quotation mark.
Note:
This does not mean your script will work! The logic of your program may be incorrect or you are attempting to show objects that do not exist on a page – these can cause errors but will not always be shown in the Error Message pane.
If the message in the Error Message pane reads Expression contains errors, then your script is in error and will not perform as you intend or expect. You will need to try and locate the problem and fix it before your program will work.
If you preview your publication that is using a script and it contains errors, a Script Console dialog will appear on the screen, this shows errors in your script – see The Script Console for more information.
Note:
The Script Console is often used to help find errors in a script (known as debugging your script).