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How to create HTML <canvas> Tag
Draw a red rectangle on the fly, and show it inside the <canvas> element:
index.html
<canvas id="myCanvas">
Your browser does not support the canvas tag.
</canvas>
<script>
let canvas = document.getElementById("myCanvas");
let ctx = canvas.getContext("2d");
ctx.fillStyle = "#FF0000";
ctx.fillRect(0, 0, 80, 80);
</script> Output should be:
Tips and Notes for HTML <canvas> Tag
Tip: Learn more about the <canvas> element in our HTML Canvas Tutorial.
What Type of Browsers will Support for HTML <canvas> Tag
Attributes for HTML <canvas> Tag
| Attribute | Value | Description |
|---|---|---|
| height | pixels | Specifies the height of the canvas. Default value is 150 |
| width | pixels | Specifies the width of the canvas Default value is 300 |
Another <canvas> example
Follow the Example
index.html
<canvas id="myCanvas">
Your browser does not support the canvas tag.
</canvas>
<script>
let c = document.getElementById("myCanvas");
let ctx = c.getContext("2d");
ctx.fillStyle = "red";
ctx.fillRect(20, 20, 75, 50);
//Turn transparency on
ctx.globalAlpha = 0.2;
ctx.fillStyle = "blue";
ctx.fillRect(50, 50, 75, 50);
ctx.fillStyle = "green";
ctx.fillRect(80, 80, 75, 50);
</script> Output should be:
Default CSS Settings For HTML <canvas> Tag
Most browsers will display the <canvas> element with the following default values:
index.html
<style>
canvas {
border:1px solid black;
}
</style>
<canvas id="myCanvas">Your browser does not support the HTML5 canvas tag.</canvas>
<script>
let c = document.getElementById("myCanvas");
let ctx = c.getContext("2d");
ctx.fillStyle = "#FF0000";
ctx.fillRect(0, 0, 80, 100);
</script>Output should be:
How to add HTML <canvas> height Attribute
A <canvas> element with a height and width of 200 pixels.
More "Try it Yourself" examples below.
Definition and Usage
The height attribute specifies the height of the <canvas> element, in pixels.
Tip: Use the width attribute to specify the width of the <canvas> element, in pixels.
Tip: Each time the height or width of a canvas is re-set, the canvas content will be cleared (see example at bottom of page).
Browser Support
The numbers in the table specify the first browser version that fully supports the attribute.
Syntax
<canvas height="pixels">
Attribute Values
| Value | Description |
|---|---|
| pixels | Specifies the height of the canvas, in pixels (e.g. "100"). Default value is 150 |
index.html
<canvas id="myCanvas" width="200" height="200" style="border:1px solid">Output should be:
How to add HTML <canvas> width Attribute
A <canvas> element with a height and width of 200 pixels:
More "Try it Yourself" examples below.
Definition and Usage
The width attribute specifies the width of the <canvas> element, in pixels.
Tip: Use the height attribute to specify the height of the <canvas> element, in pixels.
Tip: Each time the height or width of a canvas is re-set, the canvas content will be cleared (see example at bottom of page).
Browser Support
The numbers in the table specify the first browser version that fully supports the attribute.
Syntax
<canvas width="pixels">
Attribute Values
| Value | Description |
|---|---|
| pixels | Specifies the width of the canvas, in pixels (e.g. "100"). Default value is 300 |
index.html
<canvas id="myCanvas" width="200" height="200" style="border:1px solid">Output should be:
How to Clear the canvas by setting the width attribute to 400px (using JavaScript)
Follow the Example.
index.html
<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="200" height="200" style="border:1px solid">
Your browser does not support the HTML5 canvas tag.
</canvas>
<br>
<script>
const c = document.getElementById("myCanvas");
const ctx = c.getContext("2d");
ctx.fillStyle = "#92B901";
ctx.fillRect(50, 50, 100, 100);
function clearCanvas() {
c.width = 400;
}
</script>
<button onclick="clearCanvas()">Clear canvas</button>
</body>
</html>Output should be:
Category: | Web Tutorial |
Sub Category: | HTML Tag |
Uploaded by: | Admin |