Javascript doesn't seem to work

[agent2839]

Hi, so on Codeacademy I did some stuff and I'm trying it on here but no results happen why is that?
Here's the code I used:
var speed = 10
if(speed > 15) {
document.print("Too fast!");
}
else {
document.print("Too slow!");
}

It's supposed to print out Too Fast! but it doesn't seem to do that.