This is a Browser Action API.
_mouseDown simulates a mousedown on the given element.
_mouseDown( element[, isRight, combo] )
The parameters are:
_mouseDown(_button(“Mouse Down”));
_mouseDown(_button(“Mouse Down”), true); //mouseDown for a left-hand mouse
_mouseDown(_button(“Mouse Down”), false, “CTRL”); //mouseDown with CTRL key pressed
_mouseDown(_button(“Mouse Down”), false, “CTRL|SHIFT”); //mouseDown with CTRL and SHIFT keys pressed