I am executing the following Javascript on my browser (Firefox).
console.debug(\"Screen height = \"+ screen.availHeight); //outputs
Wanted to correct a thing stated in @jigfox 's answer:
https://www.w3schools.com/jsref/prop_screen_availheight.asp#:~:text=The%20availHeight%20property%20returns%20the,)%2C%20use%20the%20availWidth%20property.
The availHeight property returns the height of the user's screen, in pixels, minus interface features like the Windows Taskbar.
Tip: To get the height of the screen (excluding the Windows Taskbar), use the availHeight property.