Themousedown event is fired at anElement when a pointing device button is pressed while the pointer is inside the element.

This differs from theclick event in thatclick is fired after a full click action occurs; that is, the mouse button is pressed and released while the pointer remains inside the same element.mousedown is fired the moment the button is initially pressed.

This behavior is different frompointerdown events. When using a physical mouse,mousedown events fire whenever any button on a mouse is pressed down.pointerdown events fire only upon the first button press; subsequent button presses don't firepointerdown events.

Syntax

Use the event name in methods likeaddEventListener(), or set an event handler property.

addEventListener("mousedown", (event) => { })onmousedown = (event) => { }

Event type

AMouseEvent. Inherits fromUIEvent andEvent.

Event properties

This interface also inherits properties of its parents,UIEvent andEvent.

MouseEvent.altKeyRead only

Returnstrue if thealt key was down when the mouse event was fired.

MouseEvent.buttonRead only

The button number that was pressed (if applicable) when the mouse event was fired.

MouseEvent.buttonsRead only

The buttons being pressed (if any) when the mouse event was fired.

MouseEvent.clientXRead only

The X coordinate of the mouse pointer inviewport coordinates.

MouseEvent.clientYRead only

The Y coordinate of the mouse pointer inviewport coordinates.

MouseEvent.ctrlKeyRead only

Returnstrue if thecontrol key was down when the mouse event was fired.

MouseEvent.layerXNon-standardRead only

Returns the horizontal coordinate of the event relative to the current layer.

MouseEvent.layerYNon-standardRead only

Returns the vertical coordinate of the event relative to the current layer.

MouseEvent.metaKeyRead only

Returnstrue if themeta key was down when the mouse event was fired.

MouseEvent.movementXRead only

The X coordinate of the mouse pointer relative to the position of the lastmousemove event.

MouseEvent.movementYRead only

The Y coordinate of the mouse pointer relative to the position of the lastmousemove event.

MouseEvent.offsetXRead only

The X coordinate of the mouse pointer relative to the position of the padding edge of the target node.

MouseEvent.offsetYRead only

The Y coordinate of the mouse pointer relative to the position of the padding edge of the target node.

MouseEvent.pageXRead only

The X coordinate of the mouse pointer relative to the whole document.

MouseEvent.pageYRead only

The Y coordinate of the mouse pointer relative to the whole document.

MouseEvent.relatedTargetRead only

The secondary target for the event, if there is one.

MouseEvent.screenXRead only

The X coordinate of the mouse pointer inscreen coordinates.

MouseEvent.screenYRead only

The Y coordinate of the mouse pointer inscreen coordinates.

MouseEvent.shiftKeyRead only

Returnstrue if theshift key was down when the mouse event was fired.

MouseEvent.mozInputSourceNon-standardRead only

The type of device that generated the event (one of theMOZ_SOURCE_* constants).This lets you, for example, determine whether a mouse event was generated by an actual mouse or by a touch event (which might affect the degree of accuracy with which you interpret the coordinates associated with the event).

MouseEvent.webkitForceNon-standardRead only

The amount of pressure applied when clicking.

MouseEvent.xRead only

Alias forMouseEvent.clientX.

MouseEvent.yRead only

Alias forMouseEvent.clientY.

Examples

Seemousemove event for example code.

Specifications

Browser compatibility

See also

• Learn: Introduction to events
• mouseup
• mousemove
• click
• dblclick
• mouseover
• mouseout
• mouseenter
• mouseleave
• contextmenu
• pointerdown