How to reading chat in script?

[Dildotron]

I need the script to read what is being written in the chat and remember it in a variable. How can i do this?
For example: until I wrote "123" i = 0, but as soon as I wrote "123" in the chat - i = 1

[Aftery]

@dildotron incomprehensible

var i = 0;
on chat 
  i++;

[A Former User]

use S02
//8chars

[exit scammed]

@dildotron
S02PacketChat or C01PacketChatMessage for onPacket event

[A Former User]

oh yeah I forgot S02 will also trigger if other players say "123" use C01

[Dildotron]

@sexma can u give me pls expample script

[idk my name]

@dildotron you can use search button