window.$Viewport = { };

/*
	Viewport correspond au cadre dans lequel un document HTML est affiché dans
	une fenêtre.
*/


$Viewport.ScrollLeft = function(left) {
//--------==========-----------------

	var
		current = (window.scrollX == undefined ?
			document.documentElement.scrollLeft :
			window.scrollX
		);
	
	if (left != null && left != current) {
		window.scrollBy(left - current, 0);
		current = left;
	}
	return current;
};


$Viewport.ScrollTop = function(top) {
//--------=========----------------

	var
		current = (window.scrollY == undefined ?
			document.documentElement.scrollTop :
			window.scrollY
		);
	
	if (top != null && top != current) {
		window.scrollBy(0, top - current);
		current = top;
	}
	return current;
};


$Viewport.InnerWidth = function() {
//--------==========-------------

	return document.documentElement.offsetWidth;
};


$Viewport.InnerHeight = function() {
//--------==========--------------

	return (window.innerHeight ?
		window.innerHeight :
		document.documentElement.offsetHeight
	);
};