Untitled

<html><body>
    <script type="text/javascript">

        // Used to scale image according to aspect ratio
        function calculateAspectRatioFit(srcWidth, srcHeight, maxWidth, maxHeight) {
          var ratio = Math.min(maxWidth / srcWidth, maxHeight / srcHeight);
          return { width: srcWidth*ratio, height: srcHeight*ratio };
        }

        // Calculate aspect ratio
        function gcd (a, b) {
            return (b == 0) ? a : gcd (b, a%b);
        }
        var w = screen.width;
        var h = screen.height;
        var r = gcd (w, h);
        document.write ("<pre>");
        document.write ("Dimensions = ", w, " x ", h, "<br>");
        document.write ("Gcd        = ", r, "<br>");
        document.write ("Aspect     = ", w/r, ":", h/r);
        document.write ("</pre>");
    </script>
</body></html>
<!--
Example :

Dimensions = 1280 x 960
Gcd        = 320
Aspect     = 4:3

Dimensions = 1920 x 1080
Gcd        = 120
Aspect     = 16:9
-->