I want make a page (HTML + CSS) that fits all the space left on the browser without horizontal and vertical scrollbars.
Now you are readind this question on a web browser and, probably, you can see horizontal scrollbar. I want to use this space without using horizontal and vertical scrollbars.
I think you are looking for
window.innerWidthandwindow.innerHeightand its friends.Check out this great table on quirksmode.org for an overview on which variables are supported by which browser.
Edit: Pure CSS
In CSS you have
width: 100%andheight: 100%. If those work for your scenario, use them. To avoid scroll bars, you can useoverflow: hiddenon the body, but be very careful because this prevents scrolling completely. It depends on what you want to do.