Readonly altReturns true if the alt key was down when the mouse event was fired.
Readonly buttonThe button number that was pressed (if applicable) when the mouse event was fired.
Readonly buttonsThe buttons being depressed (if any) when the mouse event was fired.
Readonly clientXThe X coordinate of the mouse pointer in local (DOM content) coordinates.
Readonly clientYThe Y coordinate of the mouse pointer in local (DOM content) coordinates.
Readonly ctrlReturns true if the control key was down when the mouse event was fired.
Readonly detailReturns a long with details about the event, depending on the event type.
Readonly metaReturns true if the meta key was down when the mouse event was fired.
Readonly offsetXThe X coordinate of the mouse pointer between that event and the padding edge of the target node
Readonly offsetYThe Y coordinate of the mouse pointer between that event and the padding edge of the target node
Readonly pageXThe X coordinate of the mouse pointer relative to the whole document.
Readonly pageYThe Y coordinate of the mouse pointer relative to the whole document.
Readonly relatedThe secondary target for the event, if there is one.
Readonly screenXThe X coordinate of the mouse pointer in global (screen) coordinates.
Readonly screenYThe Y coordinate of the mouse pointer in global (screen) coordinates.
Readonly shiftReturns true if the shift key was down when the mouse event was fired.
Readonly xAlias for NativeMouseEvent.clientX
Readonly yAlias for NativeMouseEvent.clientY
https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent