var t1;
function vis1(){
	if (document.getElementById('sub1').style.visibility=="hidden"){
	    invis2();
	    invis3();
		document.getElementById('sub1').style.visibility="visible";
        clearTimeout(t1);
		}
	}

function invis1(){
	if (document.getElementById('sub1').style.visibility=="visible"){
		document.getElementById('sub1').style.visibility="hidden";
		t1 = setTimeout("invis1()",2500);
		}
	}
	
function vis2(){
	if (document.getElementById('sub2').style.visibility=="hidden"){
	    invis1();
	    invis3();
		document.getElementById('sub2').style.visibility="visible";
        clearTimeout(t1);
		}
	}

function invis2(){
	if (document.getElementById('sub2').style.visibility=="visible"){
		document.getElementById('sub2').style.visibility="hidden";
		t1 = setTimeout("invis2()",2500);
		}
	}
	
function vis3(){
	if (document.getElementById('sub3').style.visibility=="hidden"){
	    invis1();
	    invis2();
		document.getElementById('sub3').style.visibility="visible";
        clearTimeout(t1);
		}
	}

function invis3(){
	if (document.getElementById('sub3').style.visibility=="visible"){
		document.getElementById('sub3').style.visibility="hidden";
		t1 = setTimeout("invis2()",2500);
		}
	}