get screan size code example
Example 1: js know size of screen
alert("Your screen resolution is: " + screen.width + "x" + screen.height)
Example 2: js know size of screen displayed
var win = window,
doc = document,
docElem = doc.documentElement,
body = doc.getElementsByTagName('body')[0],
x = win.innerWidth || docElem.clientWidth || body.clientWidth,
y = win.innerHeight|| docElem.clientHeight|| body.clientHeight;
alert(x + ' × ' + y);