Thanks ! next time I'll ask if it's working xD
I thought it will work in different way

_extendTangency 1.1
* added htlm
add functions + hotkeys
b - bothsides
a - join
f - flip sides (here I've needed ~ restrict line direction - not Togo opposite tangency direction)
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script is not ended, but it has a good chunk of it, will return when i'll know more about html and moi basefunctions