HTML Canvas Drawing
Draw on the Canvas With JavaScript
All drawing on the HTML canvas must be done with JavaScript:
Example
<script>
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "#FF0000";
ctx.fillRect(0, 0, 150, 75);
</script>
亲自尝试 »
Step 1: Find the Canvas Element
First of all, you must find the <canvas> element.
This is done by using the HTML DOM method getElementById():
var canvas = document.getElementById("myCanvas");
Step 2: Create a Drawing Object
Secondly, you need a drawing object for the canvas.
The getContext() is a built-in HTML object, with properties and methods for drawing:
var ctx = canvas.getContext("2d");
Step 3: Draw on the Canvas
Finally, you can draw on the canvas.
Set the fill style of the drawing object to the color red:
ctx.fillStyle = "#FF0000";
The fillStyle property can be a CSS color, a gradient, or a pattern. The default fillStyle is black.
The fillRect(x,y,width,height) method draws a rectangle, filled with the fill style, on the canvas:
ctx.fillRect(0, 0, 150, 75);
