Cross-Browser acquisition parameters

Acquisition window position:

var leftPos = (typeof window.screenLeft == "number") ? window.screenLeft : window.screenX

var topPos = (typeof window.screenTop == "number") ? window.screenTop: window.screenY

Get a page viewport size:

var pageWidth = window.innerWidth
var pageHeight = window.innerHeight
if(typeof pageWidth != "number") {
　　if (document.compatMod == "CSS1Compat") {
　　　　pageWidth = document.documentElement.clientWidth
　　　　pageHeight = document.documentElement.clientHeight
　　} else {
　　　　pageWidth = document.body.clientWidth
　　　　pageHeight = document.body.clientHeight
　　}
}