The first one that starts to push people into territory that's usually unfamiliar to builders is the module on XSS. In that module, we cover reflected XSS which relies on the premise of untrusted data in the request being reflected back in the response.

Effortlessly finding Cross Site Script Inclusion (XSSI) & JSONP for bug bounty

innerHTML is a JavaScript tag whos property is used for DOM manipulation. More specifically, it "sets or returns the HTML content (the inner HTML) of an element." Ordinarily, this property is used to examine the current HTML source of the page, including any changes that have been made since the page was initially loaded. But, it can also be used for Cross-site Scripting(XSS).

A JavaScript Polyglot is a Cross Site Scripting (XSS) vector that is executable within various injection contexts in its raw form, or a piece of code that can be executed in multiple contexts in the application. So, a JavaScript polyglot can be multiple things at once, like a JavaScript/JPEG