If Else in my Form code

I have my code and I am getting emails from my site. I decided to add the code:
if (name eq "" or email eq "" or message eq ""){
stop ();
}else{

But it isn't working. Should I be using something else? Or is it in the wrong place? Here's how I have it now. But if I hit submit with none of the firlds completed I still receive a blank email from my site.