IsMousePressed( Button1, Button2, … )
true if a specified mouse button is pressed down. Otherwise, false.
Button1, Button2, – one of the following strings: "Left", "Right", "Middle", representing the left, right and middle buttons on a mouse. More than one Button can be included within each function. Each Button should be separated by a comma. This parameter is required.
This function will return true when a specified mouse button is being held down. This function is useful for programming keys to perform different actions in your script.