function largeur_fenetre() {
 if (window.innerWidth) return window.innerWidth;
 else if (document.body && document.body.offsetWidth) return document.body.offsetWidth;
 else return 0;
}

function hauteur_fenetre() {
 if (window.innerHeight) return window.innerHeight  ;
 else if (document.body && document.body.offsetHeight) return document.body.offsetHeight;
 else return 0;
}

function top_fenetre() {
 if(DOM) {
   if(MS) return document.body.scrollTop;
   else return window.pageYOffset;
 }
 else {
 	if (NS) return window.pageYOffset;
	else if (MS) return document.body.scrollTop;
	else return void(0);
 }
}

function left_fenetre() {
 if(DOM) {
   if (MS) return document.body.scrollLeft;
   else return window.pageXOffset;
 }
 else {
 	if (NS) return window.pageXOffset;
	else if (MS) return document.body.scrollLeft;
	else return void(0);
 }
}