When checking if a form has a Client-Side SuiteScript installed on it, the usual step is to go to the NetSuite user-interface and navigate to:
Customization > Scripting > Scripted Records.
There is a shortcut on doing this by simply loading the form and viewing the source in the browser.
Quickest way to find out if there is a script on the form:
View the source in the following browsers by:
Internet Explorer: View > Source (Alt + V, C)
Mozilla Firefox: View > Page Source (Ctrl + U)
Google Chrome: Click the paper icon > Developer > View Source (Ctrl + U)
Safari: Click the paper icon > View Source (Ctrl + Alt + U)
A new page will be open in a browser, scroll down the bottom of the page and look for a line similar to: