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HTML5 Canvas Disable Event Listener by Name

Posted by Manish Singh Articles | HTML 5 December 31, 2011
This is a simple application in a HTML 5 that perform how to HTML5 Canvas disable Event Listener by Name. We have know that the HTML5 is a advance version of the HTML that used to the developed 3D,annimated application.
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Introduction

This is a simple application in HTML 5 that performs a HTML5 Canvas disable Event Listener by Name. We know that HTML5 is an advanced version of HTML that can be used to develop 3D animated applications. The new feature of HTML5 is the canvas element for drawing. The video and audio elements for media playback. Better support for local offline storage. HTML5 will be the new standard for HTML, XHTML, and the HTML DOM. The previous version of HTML is from 1999. The web has changed a lot since then. HTML5 is still a work in progress. However, most modern browsers have some HTML5 support. HTML5 is a cooperation between the World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group.

 Step1: First open the HTML editor.

  • Open start->notepad.
  • The name of  editor is "Tom".

Untitled-1.gif

Step2: First we create the "window.onload" function. In an onload function we define the size of the canvas and set the color.
Code
window.onload = function(){
            var stage = new Kinetic.Stage("container", 578, 200);
            var circle = new Kinetic.Shape(function(){
                var canvas = this.getCanvas();
                var context = this.getContext();
                context.beginPath();
                context.arc(canvas.width / 2, canvas.height / 2, 70, 0, Math.PI * 2, true);
                context.fillStyle = "#FF00FF";
                context.fill();
                context.lineWidth = 4;
                context.stroke();
          });

circle.gif

 Step3:  Add Event Listener and set on_click event on a circle.
Code
circle.addEventListener("click.event1", function(){
                alert("First Listener");
            });
            circle.addEventListener("click.event2", function(){
                alert("Second Listener");
            });
            stage.add(circle);
            document.getElementById("remove1").addEventListener("click", function(){
                circle.removeEventListener("click.event1");
                alert("First onclick removed");
            }, false);
            document.getElementById("remove2").addEventListener("click", function(){
                circle.removeEventListener("click.event2");
                alert("Second onclick removed");
            }, false);
            document.getElementById("removeAll").addEventListener("click", function(){
                circle.removeEventListener("click");
                alert("All onclicks removed");
}, false);

1.gif

2.gif

Step4: Set button name that we have used to perform the action.
Code

<
body onmousedown="return false;">
<
div id="container">
    </div>
    <div id="buttons">
        <button id="remove1">
         Disable First Listener
        </button>
        <button id="remove2">
            Disable Second Listener
        </button>
        <button id="removeAll">
           Disable All Listeners
        </button>
    </div
>
</body>

disable.gif

Step5: Perform the complete action on HTML5, which is:
Code
<head>
    <script src="http://www.html5canvastutorials.com/libraries/kinetic-v3.2.0.js">
    </script>
    <script>
        function writeMessage(stage, message){
            var context = stage.getContext();
            stage.clear();
            context.font = "18pt Calibri";
            context.fillStyle = "black";
            context.fillText(message, 10, 25);
        }
        window.onload = function(){
            var stage = new Kinetic.Stage("container", 578, 200);
            var circle = new Kinetic.Shape(function(){
                var canvas = this.getCanvas();
                var context = this.getContext();
                context.beginPath();
                context.arc(canvas.width / 2, canvas.height / 2, 70, 0, Math.PI * 2, true);
                context.fillStyle = "#FF00FF";
                context.fill();
                context.lineWidth = 4;
                context.stroke();
            });
            circle.addEventListener("click.event1", function(){
                alert("First Listener");
            });
            circle.addEventListener("click.event2", function(){
                alert("Second Listener");
            });
            stage.add(circle);
            document.getElementById("remove1").addEventListener("click", function(){
                circle.removeEventListener("click.event1");
                alert("First onclick removed");
            }, false);
            document.getElementById("remove2").addEventListener("click", function(){
                circle.removeEventListener("click.event2");
                alert("Second onclick removed");
            }, false);
            document.getElementById("removeAll").addEventListener("click", function(){
                circle.removeEventListener("click");
                alert("All onclicks removed");
            }, false);\
        };
    </script
>
</head>
<
body onmousedown="return false;">
    <div id="container">
    </div>
    <div id="buttons">
        <button id="remove1">
         Disable First Listener
        </button>
        <button id="remove2">
            Disable Second Listener
        </button>
        <button id="removeAll">
           Disable All Listeners
        </button>
    </div
>
</body>

Output:

output.gif

output2.gif

output3.gif

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