From mIRC.hlp
on HOTLINKThe on HOTLINK event triggers when move your mouse over a specific word in a line of text in a window.
Format: on <level>:HOTLINK:<matchtext>:<*#?=!@>:<commands>
ExamplesThis event works somewhat differently from other events, and is best explained with an example:
on ^1:HOTLINK:*help*:#:{
if ($1 == helpme) return
halt
}
on 1:HOTLINK:*:*:echo clicked word $1 in line $hotline $hotlinepos