var currentpage = 1;
function opentabs(topage){
	if (currentpage == topage)return;
document.getElementById("tab" + topage).style.backgroundPosition = "bottom";
document.getElementById("tab" + currentpage).style.backgroundPosition = "top";
document.getElementById("tab" + topage + "-text").style.display = "block";
document.getElementById("tab" + currentpage + "-text").style.display = "none";
currentpage = topage;
}