client.cpp
find this: Code:

if (cvar.jump  && (usercmd->buttons & IN_JUMP) && !(me.pmFlags & FL_ONGROUND)) usercmd->buttons &= ~IN_JUMP;

replace all with this: Code:

if (cvar.jump  && (usercmd->buttons & IN_JUMP) && !(me.pmFlags & FL_ONGROUND)) usercmd->buttons &= ~IN_JUMP;
      if (cvar.autojump && me.pmFlags & FL_ONGROUND)
      {
        if (target!=-1)
        {
            usercmd->buttons |= IN_JUMP;
        }
      }
      if (cvar.duck && !(me.pmFlags & FL_ONGROUND)  && me.pmVelocity[2]>0)  usercmd->buttons |= IN_DUCK;
      if (cvar.autoduck && me.pmFlags & FL_ONGROUND)
      {
        if (target!=-1)
        {
            usercmd->buttons |= IN_DUCK;
        }
      }

cvar.cpp: Code:

REGISTER_CVAR_INT( autojump ,0)
REGISTER_CVAR_INT( autoduck ,0)

cvar.h: Code:

int autojump;
int autoduck;