problems with setInterval()

[geut]

i try doing something like this:
on (press)
{
var intervalID;
intervalID=setInterval(asdf(), 100);
}
function asdf()
{
//something;
}
but it ONLY EXECUTES THE FUNCTION ONCE. What is the problem????????

If you can point me to a working code or send one, i would really
appreciate it

[stwingy]

on (press) {
var intervalID;
intervalID = setInterval(asdf, 100);
}
// no "()"