The bind allows you to jump whenever your mouse wheel is scrolled up or down. This is commonly used by players to make bunny hopping easier, but for others, it is simply more convenient than the space bar.
Mousewheel Jump Up OnlyThis command will bind jump to only the mouse wheel scroll-up key.
bind mwheelup +jump
Mousewheel Jump Down OnlyThis command will bind jump to only the mouse wheel scroll-down key.
bind mwheeldown +jump
Mousewheel JumpThis will bind the scroll wheel to jump when you scroll up and down.
bind mwheelup +jump;bind mwheeldown +jump