//Script
set crouch1 "bind mouse1 +attack; +movedown; set toggle vstr crouch2; echo ^0>^7Crouch script^0: ^7Off"
set crouch2 "bind mouse1 +vstr crouchOn crouchOff; set toggle vstr crouch1; echo ^0>^7Crouch script^0: ^7On"
set toggle vstr crouch1
set crouchOn "+attack; +movedown; cg_fov 90"
set crouchOff "-attack; -movedown; -movedown; cg_fov 100"
//Binded key
Bind key mouse1 vstr toggle
Save this as a or add it in your cfg and execute it in game