var tab 	= new Array('un','deux','trois','quatre');
	var menu 	= new Array('accueil','competence','contact','lien');
	function change_div(id,m) 
	{
		for(i=0;i<menu.length;i++)
		{
			div = document.getElementById(menu[i]);
			if (menu[i]==m)
				div.style.color='#AA0000';
			else
				div.style.color='#338888';
		}
		for(i=0;i<tab.length;i++)
		{
			div = document.getElementById(tab[i]);
			/*changeOpac(0, tab[i])*/
			div.style.display='none';
		}
		for(i=0;i<tab.length;i++)
		{
			div = document.getElementById(tab[i]);
			if (id==tab[i])
			{
				div.style.display='block';
				/*currentOpac(id, 100, 1000);*/
			}
		}
		if(id=='quatre')
			document.getElementById('ecran_droit').style.display='none';
		else
		{
			document.getElementById('ecran_droit').style.display='block';
			alea1= Math.floor(Math.random() * lien.length);
			while(alea1==(alea2=Math.floor(Math.random() * lien.length)));
			document.getElementById("oImg_top").src = lien[alea1][0];
			document.getElementById("oImg_bottom").src = lien[alea2][0];
		}
	}

		
	
/********************************************************************************/	
/*************************** OPACITY *******************************************/	
/********************************************************************************/
	
	function opacity(id, opacStart, opacEnd, millisec) { 
		//alert(id+" - strart : "+opacStart);
		//speed for each frame 
		var speed = Math.round(millisec / 100); 
		var timer = 0; 
	
		//determine the direction for the blending, if start and end are the same nothing happens 
		if(opacStart > opacEnd) { 
			for(i = opacStart; i >= opacEnd; i--) { 
				setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
				timer++; 
			} 
		} else if(opacStart < opacEnd) { 
			for(i = opacStart; i <= opacEnd; i++) 
				{ 
				setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
				timer++; 
			} 
		} 
	} 
	
	//change the opacity for different browsers 
	function changeOpac(opacity, id) { 
		var object = document.getElementById(id).style; 
		object.opacity = (opacity / 100); 
		object.MozOpacity = (opacity / 100); 
		object.KhtmlOpacity = (opacity / 100); 
		object.filter = "alpha(opacity=" + opacity + ")"; 
	}
	function currentOpac(id, opacEnd, millisec) { 
		//standard opacity is 100 
		var currentOpac = 100; 
		 
		//if the element has an opacity set, get it 
		if(document.getElementById(id).style.opacity < 100) { 
			currentOpac = document.getElementById(id).style.opacity * 100; 
		} 
	
		//call for the function that changes the opacity 
		opacity(id, currentOpac, opacEnd, millisec) 
	}