Stop action if an error appears - CS5/Javascript

Question

Hey all!
Here's what I'm trying to do: I have an action that does lots of things then call one script then it closes the file.
When there's something wrong with the name of the file that the script is searching it pop's up an alert box.
Here's the thing, after the alert box I want the script to STOP running and then DONT close the file that is the next step of the action that calls the script.
(It occurred me that if necessary I can get that close action into the script to make it simple, then all I got to do is to stop the script, is that right?)
And if its possible that after this error occours PS brings me that dialog box asking if I want to keep it on working with the batch or stop, but this is optional.
Can anyone help me? :]
Ty for all, and plz forgive any grammatical errors, I'm brazilian.

Answer 1

Yes, I am doing a IF check. Its like this:
if (semtam >0 )
              alert("O nome do arquivo não possui distinção de tamanho. Por favor, corrija-o. Este é o arquivo " + refvar + ".", "Erro na nomenclatura")
"semtam" is a var that i created to check if the filename contains a certain word.
After the alert pop's up that's when the script has to break.
If the var is null then it just keep rolling and does like 5 different kinds of save and that's working just fine, I just don't know how to stop and i didn't wanted to get the whole script inside the "if (semtam <1 )" or something like that. I can do that, but i just think that's gotta be another way, right?
Ty for the attention.