screen width vs visible portion

Question

I have a little problem with JavaScript, to get the screen width we use screen.width which returns the overall screen resolution, is there a command to get the resolution of

Answer 1

function width(){
   return window.innerWidth 
       || document.documentElement.clientWidth 
       || document.body.clientWidth 
       || 0;
}

function height(){
   return window.innerHeight 
       || document.documentElement.clientHeight 
       || document.body.clientHeight 
       || 0;
}

Use them to return the height() or width() of the visible window.

JSFiddle example.