positionIt = function() {
				if( document.getElementById ) {
					// Get a reference to BoxId and measure its width.
					var div0 = document.getElementById( "Bkg" );
					var div0Width = div0.offsetWidth ? div0.offsetWidth : div0.style.width ? parseInt( div0.style.width ) : 0;
					
					// Calculating MarginX so the BoxId will be centered in the viewport.
					var WidthT = div0Width;								/*Body_Width = Element_Gauche + Element_Droite*/
					var MarginX = ( getViewportWidth() - WidthT ) / 2;		/*Margin_Body = (Viewport_Width - Body_Width) divisé par 2*/
					
					// If MarginXhave become smaller than 0, make them 0.
					if( MarginX < 0 ) MarginX = 0;
					
					// Position the BoxId in the center of the page and make it visible.
					div0.style.left = MarginX + "px";
				}
			}
			
			getViewportWidth = function() {
				var width = 0;
				if( document.documentElement && document.documentElement.clientWidth ) {
					width = document.documentElement.clientWidth;
				}
				else if( document.body && document.body.clientWidth ) {
					width = document.body.clientWidth;
				}
				else if( window.innerWidth ) {
					width = window.innerWidth - 18;
				}
				return width;
			};
			
			getViewportHeight = function() {
				var height = 0;
				if( document.documentElement && document.documentElement.clientHeight ) {
					height = document.documentElement.clientHeight;
				}
				else if( document.body && document.body.clientHeight ) {
					height = document.body.clientHeight;
				}
				else if( window.innerHeight ) {
					height = window.innerHeight - 18;
				}
				return height;
			};
			
			window.onload = positionIt;
			window.onresize = positionIt;