ajax - "Screen is not a member of My.MyComputer" -

i interested in using ajax (via/with visual studio 2012) make webpage more dynamic. terribly confused error getting..

'screen' not member of "my.mycomputer"

all want screen size. i've looked on google , found every time way is:

my.computer.screen.bounds.height my.computer.screen.bounds.width

screen.primaryscreen.bounds.width screen.priamryscreen.bounds.height

i error every time.. it's little different second method; says:

'screen' hasn't been declared.

in javascript lowercase screen:

screen.height; screen.width;

demo: jsfiddle

in .net @georgejohnston pointed out need:

the screen object found in namespace, system.windows.forms not going in web forms project default.

Live