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my code takes a mouse position. Mobile browser supports html5. but cannot use MouseUp mouseDown how can i fix it? 

<!DOCTYPE HTML>
<html>

<head>

  <body style="background-color:3F6E6F;">
    <style>
      body {
        margin: 0px;
        padding: 0px;
      }
    </style>
</head>

<body>

  <canvas id="myCanvas" width="1200" height="1000" onmousedown="mouseDown()" onmouseup="mouseUp()"></canvas>
  <p id="demo"></p>


  <script>
    var depx = 0;
    var depy = 0;
    var flag = 0;

    function writeMessage(canvas, message) {
      var context = canvas.getContext('2d');
      context.clearRect(0, 0, canvas.width, canvas.height);
      context.font = '18pt Calibri';
      context.fillStyle = 'black';
      context.fillText(message, 10, 25);
    }


    function getMousePos(canvas, evt) {
      var rect = canvas.getBoundingClientRect();
      return {
        x: evt.clientX - rect.left,
        y: evt.clientY - rect.top
      };
    }


    var canvas = document.getElementById('myCanvas');
    var context = canvas.getContext('2d');


    function mouseDown() {
      canvas.addEventListener("mousemove", myFunction);
    }




    function myFunction(evt) {
      var mousePos = getMousePos(canvas, evt);
      if (flag == 0) {
        depx = mousePos.x;
        depy = mousePos.y;
      }
      flag = 1;


      var message = 'Mouse position: ' + mousePos.x + ',' + mousePos.y + ' abs position ' + (mousePos.x - depx) + ',' + (mousePos.y - depy);
      writeMessage(canvas, message);
    }

    function mouseUp() {
      flag = 0;
      canvas.removeEventListener("mousemove", myFunction);
    }
  </script>

</body>

</html>

my code takes a mouse position. Mobile browser supports html5. but cannot use MouseUp mouseDown how can i fix it? 

<!DOCTYPE HTML>
<html>

<head>

  <body style="background-color:3F6E6F;">
    <style>
      body {
        margin: 0px;
        padding: 0px;
      }
    </style>
</head>

<body>

  <canvas id="myCanvas" width="1200" height="1000" onmousedown="mouseDown()" onmouseup="mouseUp()"></canvas>
  <p id="demo"></p>


  <script>
    var depx = 0;
    var depy = 0;
    var flag = 0;

    function writeMessage(canvas, message) {
      var context = canvas.getContext('2d');
      context.clearRect(0, 0, canvas.width, canvas.height);
      context.font = '18pt Calibri';
      context.fillStyle = 'black';
      context.fillText(message, 10, 25);
    }


    function getMousePos(canvas, evt) {
      var rect = canvas.getBoundingClientRect();
      return {
        x: evt.clientX - rect.left,
        y: evt.clientY - rect.top
      };
    }


    var canvas = document.getElementById('myCanvas');
    var context = canvas.getContext('2d');


    function mouseDown() {
      canvas.addEventListener("mousemove", myFunction);
    }




    function myFunction(evt) {
      var mousePos = getMousePos(canvas, evt);
      if (flag == 0) {
        depx = mousePos.x;
        depy = mousePos.y;
      }
      flag = 1;


      var message = 'Mouse position: ' + mousePos.x + ',' + mousePos.y + ' abs position ' + (mousePos.x - depx) + ',' + (mousePos.y - depy);
      writeMessage(canvas, message);
    }

    function mouseUp() {
      flag = 0;
      canvas.removeEventListener("mousemove", myFunction);
    }
  </script>

</body>

</html>

Here is the Html and Css code, please have a look and help me with some changes if you find any that would help.

  • javascript
  • html
  • mobile
  • browser
Share Improve this question edited Nov 11, 2018 at 12:11 Cœur 38.7k26 gold badges202 silver badges277 bronze badges asked Nov 28, 2016 at 7:16 user6355116user6355116 1
  • this is what you should use for mobile. – Kevin Kloet Commented Nov 28, 2016 at 7:22
Add a comment  | 

2 Answers 2

Reset to default 19

Because touch events are not mouse events. If you add a mouse, you could get mouse events.

For touch events, you need to use 

pointerup
pointerdown

events/eventlistener. Read more about pointerup and pointerdown.

Usage: Add addEventListener for pointer as well.

document.getElementById('elem1').addEventListener('pointerdown', methodForPointerDown, false);
document.getElementById('elem1').addEventListener('pointerup', methodForPointerUp, false);

There is an alternative for MouseUp and mouseDown for mobile browsers sice they dont use a mouse.

You can use touchstart and touchend instead of them in your case for a mobile browser.

There is a link here for reference

Here is another set of event listeners for mobile devices.

Pointer Events

Here is an example how you detect the pointer device type with pointer event listeners

Detecting the type of input from a user

window.addEventListener("pointerdown", detectInputType, false);

function detectInputType(event) {
    switch(event.pointerType) {
        case "mouse":
            /* mouse input detected */
            break;
        case "pen":
            /* pen/stylus input detected */
            break;
        case "touch":
            /* touch input detected */
            break;
        default:
            /* pointerType is empty (could not be detected)
            or UA-specific custom type */
    }
}

Hope this helps you..

本文标签： javascriptWhy (MouseUp mouseDown) are not working on mobile browserStack Overflow

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