function changer_image(nom_td,sens)
{
	if(sens==1)
	{
		document.getElementsByTagName('td')[nom_td].style.backgroundImage='url(\'images/common/menu1_fond2.gif\')';
		document.getElementsByTagName('a')[nom_td].style.color='white';
	}
	else
	{
		document.getElementsByTagName('td')[nom_td].style.backgroundImage='url(\'images/common/menu1_fond1.gif\')';
		document.getElementsByTagName('a')[nom_td].style.color='black';
	}	
}



function cacher(id)
{
	if(id="tout")
	{
		if(document.getElementById)
    		document.getElementById("prod").style.visibility ="hidden";
  		else if(document.all)
    		document.all["prod"].style.visibility ="hidden";
		
		if(document.getElementById)
    		document.getElementById("contacts").style.visibility ="hidden";
  		else if(document.all)
    		document.all["contacts"].style.visibility ="hidden";
	}
	else
	{
		if(document.getElementById)
    		document.getElementById(id).style.visibility ="hidden";
  		else if(document.all)
    		document.all[id].style.visibility ="hidden";
	}

	/*document.getElementById('about').style.visibility ="hidden";
	document.getElementById('products').style.visibility ="hidden";
	document.getElementById('science').style.visibility ="hidden";
	document.getElementById('leader').style.visibility ="hidden";*/
}
function montrer(id)
{
	if(document.getElementById)
    	document.getElementById(id).style.visibility ="visible";
  	else if(document.all)
    	document.all[id].style.visibility ="visible";
	//document.getElementById(id).style.visibility ="visible";
}
function toutsauf(id)
{
	cacher('tout');
	montrer(id);
}