On active
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The on ACTIVE event trigger when a window in mIRC is activated.
on <level>:ACTIVE:<*#?=!@>:<commands>
The above event triggers whenever a window in mIRC is activated. The $active identifier returns the name of the currently active window, and the $lactive identifier returns the name of the window that was just de-activated. The status window is called "Status Window".
Note that one or both $active or $lactive can return $null.
Example
On *:ACTIVE:*: { echo -a My active window: $active My deactived window: $lactive }
This event will trigger whenever you change the active window in your mIRC.
See Also
Take a look at the On Appactive event to react on mIRC becoming active or inactive.