Inject Script
Inject a script (JavaScript) into the current page and run it. This is distinctly different from Execute Script, which runs the script in the Virtual User (in Load Tester) rather than in the web page.
Inject Script uses a single datasource to provide the script that will be sent to the browser and executed. As an example, this simple 1-line script will enter a value into a text field with ID=”user_login”:
A non-null return value from the script indicates an error. The return value will be converted to a string and used as the error message.