function getScrollXY() { // torna i pixel x e y scrollati
	var scrOfX = 0, scrOfY = 0;
	if( typeof( window.pageYOffset ) == 'number' ) {
		//Netscape compliant
		scrOfY = window.pageYOffset;
		scrOfX = window.pageXOffset;
	} else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
		//DOM compliant
		scrOfY = document.body.scrollTop;
		scrOfX = document.body.scrollLeft;
	} else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
		//IE6 standards compliant mode
		scrOfY = document.documentElement.scrollTop;
		scrOfX = document.documentElement.scrollLeft;
	}
	return [ scrOfX, scrOfY ];
}
	
/* -------------------------------------------------------------------------------------------------------------- */

function getViewportSize(){ // torna le dimensioni dell'area utile
	var size=[0, 0]; 
	if (typeof window.innerWidth != "undefined"){ 
		size=[window.innerWidth, window.innerHeight];
	} 
	else if (typeof document.documentElement != "undefined" && typeof document.documentElement.clientWidth != "undefined" && document.documentElement.clientWidth != 0) {
		size=[document.documentElement.clientWidth, document.documentElement.clientHeight]; 
	}
	else{
		size=[document.getElementsByTagName("body")[0].clientWidth, document.getElementsByTagName("body")[0].clientHeight]; 
	}
	return size; 
}