First, then, learn to write simply and clearly (I’m not referring to English).
Better a clear script example than a mess inside the script, no matter if is well explained.
Example:
http://forum.mikrotik.com/t/prevent-the-script-from-running-if-it-is-already-running/167618/1
Anyway, there are errors in what you wrote.
An example above all is the fact that it does not take into account the dynamic rules, which should not be preceded…