Form.clientScriptModulePath function is the relative path to the client script file to be used in this form.
Use this property when attaching an on demand client script to a server script.
General syntax is as:
objForm.clientScriptModulePath = 'SuiteScripts/formBehavior.js';
Note that the path to be mentioned is the relative path of the file.
It is useful in cases when we need to call a client script from any other scripts such as Suitelett scripts.