window.onload = function() {
var oDiv = document.getElementById("tab");
var oLi = oDiv.getElementsByTagName("div")[0].getElementsByTagName("li");
var aCon = oDiv.getElementsByTagName("div")[1].getElementsByTagName("div");
var timer = null;
for (var i = 0; i < oLi.length; i++) {
oLi[i].index = i;
oLi[i].onclick = function() {
show(this.index);
}
}
function show(a) {
index = a;
var alpha = 0;
for (var j = 0; j < oLi.length; j++) {
oLi[j].className = "";
aCon[j].className = "";
aCon[j].style.opacity = 0;
aCon[j].style.filter = "alpha(opacity=0)";
}
oLi[index].className = "cur";
clearInterval(timer);
timer = setInterval(function() {
alpha += 2;
alpha > 100 && (alpha = 100);
aCon[index].style.opacity = alpha / 100;
aCon[index].style.filter = "alpha(opacity=" + alpha + ")";
alpha == 100 && clearInterval(timer);
},
5)
}
}