Элемент: mouseup событие

Событие mouseup возникает на Element, когда кнопка на аппаратном манипуляторе курсора (на мыши или трекпаде) отпущена, в то время как указатель находится на элементе. Событие mouseup является противоположным mousedown событию.

Bubbles Да
Отменяемое  Да
Interface MouseEvent
Event handler property onmouseup

Примеры

The following example uses the mousedown, mousemove, and mouseup events to allow the user to draw on an HTML5 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

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

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 === true) {
    drawLine(context, x, y, e.offsetX, e.offsetY);
    x = e.offsetX;
    y = e.offsetY;
  }
});

window.addEventListener('mouseup', e => {
  if (isDrawing === true) {
    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

Спецификация

Specification Status
UI Events
Определение 'mouseup' в этой спецификации.
Рабочий черновик
Document Object Model (DOM) Level 3 Events Specification
Определение 'mouseup' в этой спецификации.
Устаревшая

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