[jQuery] Getting two animations together on an element

[jQuery] Getting two animations together on an element


Most of the time I want to have two animations after one aother and I
can fet it by using call back. But for something I am writing I want
two animation namely height and opacity occurring together on an
element to create a curtain like effect but whatever I tried it seems
one animation completes before other starts.
Can someone please educate me as to how I can achieve it?
for simplest code if I say
$("#transbox").animate({height:0},1000)
$("#transbox").animate({opacity:0.1},1000);
or
$("#transbox").animate({height:0},3000).animate({opacity:0.1},1000);
but none does what I intend it to do.