function ReplaceMenu() 
{ 
	var offsetInfo = "" 
	var Y = document.body.scrollTop;
	if((Y) <= 105)
	{
		document.getElementById('menu_gauche').style.top = 0;//pixelTop
	}
	else
	{
		document.getElementById('menu_gauche').style.top = Y - 105;                  
	}
	//document.getElementById('gris').style.top = Y;
}