Any way we can set window to full width and height?

[tetron432]

I want to make a window full width and height in the browser screen. However, when I tried doing:

<div class="window" style="width: 100%;height: 100%">

There always seems to be gaps of space between the left, right, top, and bottom sides of the screen and the window, as shown here:

Is there a way so that that the window can be set to full screen without any of the gaps of space?

[juanigaray]

That's probably your user-agent giving some of the ancestor elements a padding or a margin. Try opening the devtools and hovering over the elements in your document source code, while looking at them being highlighted in the page proper.