All major browsers offer a robust set of inspection and development tools. They can be opened either from the browser menu, or with keyboard commands.
Open the website you wish to inspect, then open the browser developer tools The following keys (or key press combinations) will open the inspection tools.
- Windows / Linux operating system: F12 (single key press), or Control-Shift-I (pressed in combination)
- Mac operating system: Command-Option-I (pressed in combination).
The ‘Elements’ tab allows one to inspect and manipulate the HTML and CSS within a web page. The ‘Console’ tab allows one to inspect and run JavaScript. It is also where PopupMaker displays the output from its debugger tools, and where JavaScript errors can be found.