Element: mousemove event

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The mousemove event is fired at an element when a pointing device (usually a mouse) is moved while the cursor's hotspot is inside it.

These events happen whether or not any mouse buttons are pressed. They can fire at a very high rate, depends on how fast the user moves the mouse, how fast the machine is, what other tasks and processes are happening, etc.

Syntax

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

addEventListener("mousemove", (event) => {}); onmousemove = (event) => {};

Event type

A MouseEvent. Inherits from UIEvent and Event.

Event properties

This interface also inherits properties of its parents, UIEvent and Event.

MouseEvent.altKeyRead only: Returns true if the alt 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 in viewport coordinates.
MouseEvent.clientYRead only: The Y coordinate of the mouse pointer in viewport coordinates.
MouseEvent.ctrlKeyRead only: Returns true if the control 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: Returns true if the meta 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 last mousemove event.
MouseEvent.movementYRead only: The Y coordinate of the mouse pointer relative to the position of the last mousemove 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 in screen coordinates.
MouseEvent.screenYRead only: The Y coordinate of the mouse pointer in screen coordinates.
MouseEvent.shiftKeyRead only: Returns true if the shift key was down when the mouse event was fired.
MouseEvent.mozInputSourceNon-standardRead only: The type of device that generated the event (one of the MOZ_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 for MouseEvent.clientX.
MouseEvent.yRead only: Alias for MouseEvent.clientY.

Examples

The following example uses the mousedown, mousemove, and mouseup events to allow the user to draw on an HTML canvas. Its functionality is simple: the thickness of the line is set to 1, and the color is always black.

When the page loads, constants myPics and context are created to store a reference to the canvas and the 2d context we will use to draw.

Drawing begins when the mousedown event fires. First we store the x and y coordinates of the mouse pointer in the variables x and y, and then set isDrawing to true.

As the mouse moves over the page, the mousemove event fires. If isDrawing is true, the event handler calls the drawLine function to draw a line from the stored x and y values to the current location.

When the drawLine() function returns, we adjust the coordinates and then save them in x and y.

The mouseup event draws the final line segment, sets x and y to 0, and stops further drawing by setting isDrawing to false.

HTML

html

<h1>Drawing with mouse events</h1> <canvas id="myPics" width="560" height="360"></canvas>

CSS

css

canvas { border: 1px solid black; width: 560px; height: 360px; }

JavaScript

// When true, moving the mouse draws on the canvas let isDrawing = false; let x = 0; let y = 0; const myPics = document.getElementById("myPics"); const context = myPics.getContext("2d"); // event.offsetX, event.offsetY gives the (x,y) offset from the edge of the canvas. // Add the event listeners for mousedown, mousemove, and mouseup myPics.addEventListener("mousedown", (e) => { x = e.offsetX; y = e.offsetY; isDrawing = true; }); myPics.addEventListener("mousemove", (e) => { if (isDrawing) { drawLine(context, x, y, e.offsetX, e.offsetY); x = e.offsetX; y = e.offsetY; } }); window.addEventListener("mouseup", (e) => { if (isDrawing) { drawLine(context, x, y, e.offsetX, e.offsetY); x = 0; y = 0; isDrawing = false; } }); function drawLine(context, x1, y1, x2, y2) { context.beginPath(); context.strokeStyle = "black"; context.lineWidth = 1; context.moveTo(x1, y1); context.lineTo(x2, y2); context.stroke(); context.closePath(); }

Result

Specifications

Specification
UI Events # event-type-mousemove
HTML # handler-onmousemove