function detectBrowserSize() {
var myWidth = 0, myHeight = 0;
if (typeof (window.innerWidth) == 'number') {
//Non-IE
myWidth = window.innerWidth;
myHeight = window.innerHeight;
} else if (document.documentElement && (document.documentElement.clientWidth || document.documentElement.clientHeight)) {
//IE 6+ in 'standards compliant mode'
myWidth = document.documentElement.clientWidth;
myHeight = document.documentElement.clientHeight;
} else if (document.body && (document.body.clientWidth || document.body.clientHeight)) {
//IE 4 compatible
myWidth = document.body.clientWidth;
myHeight = document.body.clientHeight;
}
alert(myWidth + ' - ' + myHeight)
}

//http://stackoverflow.com/questions/1587499/detecting-browser-client-area-size-on-wide-screen-using-javascript

function detectBrowserSize() {
if (navigator.appName.indexOf("Microsoft")!=-1)
{
w = document.body.clientWidth;
h = document.body.clientHeight;
}
else
w = window.innerWidth;
h = window.innerHeight;

// objW e objH relacionados abaixo é o width e height do objeto que sofrera o drag e drop
// acrescentei + 10 pra não ficar colado nas bordas finais.

limitDragX = w - (objW + 10);
limitDragY = h - (objH + 10);
}