You can just use return
.
function myfunction() {
if(a == 'stop')
return;
}
This will send a return value of undefined
to whatever called the function.
var x = myfunction();
console.log( x ); // console shows undefined
Of course, you can specify a different return value. Whatever value is returned will be logged to the console using the above example.
return false;
return true;
return "some string";
return 12345;