function toDiv1()
{
   	document.getElementById("div4").style.display = "none";
	document.getElementById("div3").style.display = "none";
	document.getElementById("div2").style.display = "none";
    document.getElementById("div1").style.display = "block";
}
function toDiv2()
{
   	document.getElementById("div4").style.display = "none";
	document.getElementById("div3").style.display = "none";
	document.getElementById("div1").style.display = "none";
    document.getElementById("div2").style.display = "block";
}
function toDiv3()
{
   	document.getElementById("div4").style.display = "none";
	document.getElementById("div1").style.display = "none";
	document.getElementById("div2").style.display = "none";
    document.getElementById("div3").style.display = "block";
}
function toDiv4()
{
   	document.getElementById("div1").style.display = "none";
	document.getElementById("div3").style.display = "none";
	document.getElementById("div2").style.display = "none";
    document.getElementById("div4").style.display = "block";
}