运行效果截图如下：
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>canvas绘制矩形</title>
<script type="text/javascript" >
function draw(id) {
var canvas = document.getElementById("canvas")
if (canvas) {
var context = canvas.getContext("2d")
context.fillStyle = "#DDDDDD"
context.fillRect(0, 0, 400, 400)
context.strokeStyle = "black"
context.fillStyle = "gray"
context.lineWidth = 5
context.fillRect(0,0,200,300)
context.strokeRect(0,0,200,200)
} else {
return
}
}
function drawBorder(id) {
var canvas = document.getElementById("canvas2")
if (canvas) {
var context = canvas.getContext("2d")
context.fillStyle = "red"
context.strokeStyle = "black"
context.lineWidth = 5
context.fillRect(0,0, 300, 200)
context.strokeRect(0,0,300,200)
} else {
return
}
}
window.onload = function () {
draw("canvas")
drawBorder("canvas2")
}
</script>
</head>
<body>
<canvas id="canvas" width="400" style="background:red" height="400"></canvas>
<hr />
<canvas id="canvas2" width="400" height="400"></canvas>
</body>
</html>
<!DOCTYPE html><html>
<head>
<meta http-equiv="Content-Type" content="text/html charset=utf-8" />
<title>_</title>
<script src="http://libs.baidu.com/jquery/1.11.1/jquery.min.js"></script>
</head>
<script type="text/javascript">
$(function(){
var canvas = document.getElementById("canvas")
var ctx = canvas.getContext("2d")
var img = new Image()
img.src = "https://ss0.bdstatic.com/5aV1bjqh_Q23odCf/static/superman/img/logo/bd_logo1_31bdc765.png"
img.onload = function(){
draw(this, 10, 10)
}
function draw(img, x, y){
if(img){
this.img = img
this.x = x
this.y = y
this.width = img.width
this.height = img.height
}else{
if(!this.img) return
ctx.clearRect(this.x, this.y, this.x + this.width, this.y + this.height)
img = this.img
x += this.x
y += this.y
this.x = x
this.y = y
}
ctx.drawImage(img, x, y)
}
var size = 5
$(document.body).keydown(function(event){
switch(event.keyCode){
case 37: draw(null, -size, 0) break
case 38: draw(null, 0, -size) break
case 39: draw(null, size, 0) break
case 40: draw(null, 0, size) break
}
})
})
</script>
<body>
<canvas id="canvas" width="1000" height="500"></canvas>
</body>
</html>
