The <canvas> tag is used to draw graphics on the page using a scripting language like JavaScript, by creating a drawing area. The default width is 300px and heigh 150px, but you can make it any size desired by including the width and height attributes.

<canvas id="my_canvas" width="500" height="500">
    Your browser does not support the canvas tag.
</canvas>

Once you have the canvas on the page, JavaScript is used to actually draw the shapes, gradients, and text. What is drawn on the canvas is only limited by your JavaScript skills.

The JavaScript to control the drawing would be placed in the document head, or better yet, linked to in its own scripts document.

Draw a Series of Lines

<script>
    var canvas = document.getElementById('my_canvas');
    var ctx = canvas.getContext('2d');
    ctx.moveTo(0,0);
    ctx.lineTo(500,500);
    ctx.lineTo(0,100);
    ctx.lineTo(200,0);
    ctx.lineTo(0,0);
    ctx.stroke();
</script>

Draw a Circle

<script>
    var canvas = document.getElementById('my_canvas');
    var ctx = canvas.getContext('2d');
    ctx.beginPath();
    ctx.arc(250, 250, 200, 0, 2 * Math.PI);
    ctx.stroke();
</script>

Create a Gradient

<script>
    var canvas = document.getElementById('my_canvas');
    var ctx = canvas.getContext('2d');
    // create gradient
    var grd = ctx.createLinearGradient(0, 0, 500, 400);
    grd.addColorStop(0, 'red');
    grd.addColorStop(1, 'green');
    // fill with gradient
    ctx.fillStyle = grd;
    ctx.fillRect(0, 0, 500, 500);
</script>

Write Text to the Canvas

<script>
    var canvas = document.getElementById('my_canvas');
    var ctx = canvas.getContext('2d');
    ctx.font = '30px Helvetica';
    ctx.fillText('This is being written to the canvas.', 10, 250);
</script>

The following attributes can be used within the <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)

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