function changeColor(element, color)
	{
		element.style.backgroundColor=color;
	}
	
	function showSub(which)
	{
		hideSubMenus();
		document.getElementById(which).style.visibility = 'visible'; 
	}
	
	function hideSub(which)
	{
		document.getElementById(which).style.visibility = 'hidden';

	}
	
	function hideMenus()
	{
		document.getElementById('products').style.visibility = 'hidden'; 
		document.getElementById("technology").style.visibility = 'hidden'; 
		document.getElementById("company").style.visibility = 'hidden';
		document.getElementById("news").style.visibility = 'hidden'; 
		document.getElementById("contact").style.visibility = 'hidden'; 	
		document.getElementById("reference").style.visibility = 'hidden'; 	
		hideSubMenus();	
	}
	
	function hideSubMenus()
	{
		document.getElementById("1_1").style.visibility = 'hidden';
		document.getElementById("1_2").style.visibility = 'hidden';
		document.getElementById("1_3").style.visibility = 'hidden';
		document.getElementById("1_4").style.visibility = 'hidden';

		document.getElementById("2_1").style.visibility = 'hidden';
		document.getElementById("2_2").style.visibility = 'hidden';
		document.getElementById("2_3").style.visibility = 'hidden';
		document.getElementById("2_4").style.visibility = 'hidden';
		
		document.getElementById("3_1").style.visibility = 'hidden';
		document.getElementById("3_2").style.visibility = 'hidden';
	}