[javascript] How to get the 'height' of the screen using jquery

I want to set something in the middle of the screen

thanks

use with responsive website (view in mobile or ipad)

jQuery(window).height();   // return height of browser viewport
jQuery(window).width();    // return width of browser viewport

rarely use

jQuery(document).height(); // return height of HTML document
jQuery(document).width();  // return width of HTML document

$(window).height();

To set anything in the middle you can use CSS.

<style>
#divCentre 
{ 
    position: absolute;
    left: 50%;
    top: 50%;
    width: 300px;
    height: 400px;
    margin-left: -150px;
    margin-top: -200px;
}
</style>
<div id="divCentre">I am at the centre</div>