With Run Javascript on a web page, you can run javascript codes to interac with a webpage elements. Very basic examples would be clicking a button, inputing/copying text, etc in a webpage. You need to have some knowdledge of HTML, Javascript and how to inspect web elements. Following is an example of copying text from web using element’s id:

Run Script command can be used to run codes written in other languages, such as Python, JScript, etc.