WoW:API CameraOrSelectOrMoveStart

Simulates depressing the left mouse button. When used alone, puts you into a "mouselook" mode until you press and release the actual left mouse button, or use the CameraOrSelectOrMoveStop command.

Example:

/script CameraOrSelectOrMoveStart();

Used in conjunction with the CameraOrSelectOrMoveStop command, simulates a left mouse click.

Example:

/script CameraOrSelectOrMoveStart();

/script CameraOrSelectOrMoveStop();

Result is context sensitive, as the name of the command itself implies; is not a "true" left mouseclick, as it will not activate UI buttons.