Name of this effect, or related plugin

What do you call this kind of effect, that Tumbler has, where content are displayed and animated?

http://www.tumblr.com/

Thank y开发者_StackOverflow中文版ou in advance...

---

There are 2 div's here,

1st div - till the copyright statement and

2nd div - 30 reasons you'll love Tumblr

When you hit the down arrow, div1 slides up, the jQuery code will look something like this

$("#div1").slideUp(1000);

this slidUp will allow another div, div3 - The easiest way to blog to appear.

and the same is done when you hit the home button,

The div3 slides down, the jQuery code will look something like this,

$("#div3").slideDown1(1000);

this slideDown will let div1 appear again.

---

It's generally called a slider.