jquery get current screen width

Reference article

<script type="text/javascript"> 
$(document).ready(function() 
{ 
alert($(window).height()); //height of the visible area of ​​the browser's current window 
alert($(document). height()); //The height of the browser's current window document 
alert($(document.body).height());//The height of the browser's current window document body 
alert($(document.body).outerHeight(true ));//The total height of the document body of the browser's current window includes border padding margin 
alert($(window).width()); //The width of the visible area of ​​the browser's current window 
alert($(document).width() );//Browser current window document object width 
alert($(document.body).width());//Browser current window document body height 
alert($(document.body).outerWidth(true)); //The total width of the browser's current window document body includes border padding margin 
} 
) 
</script>