Q:

Stop JavaScript script execution

I have a form which is being submitted by ajax.   Before submission, there's a function which checks if a textarea in the form is empty before submitting.   if it is empty, I need to stop the script and show a modal box AND prevent the submission of data to proceed. 
How do I stop execution?   Do I use 
break;

? 

A:

Nope, you generally use return;
Of course the exact details will vary depending on your implementation.  You may need to return false;, for instance, and manually check the return value to see whether or not to keep executing script in the calling function. 

A:

Try this:    
$('#target').submit(function() {
  alert('Handler for .submit() called.'); 
  return false;
});

