4
空的错误,我有这样的代码:Canvas是在JavaScript
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
canvas{border:#666 1px solid;}
</style>
<script type="text/javascript">
var canvas = document.getElementById("canvas"),
context = canvas.getContext("2d"),
playerimage = new Image(),
x = canvas.width/2, //align to centre of the screen
y = canvas.height/2, //same as above
speed = 5, //speed for the player to move at
width = 50, //width of the player
height = 50; //height of the player
function init() {
playerimage.src = "ninja.png"; //path to the image to use for the player
canvas.addEventListener("keypress", update);
}
function update(event) {
if (event.keyCode == 38) {
y -= speed; //going up
}
if (event.keyCode == 40) {
y += speed; //going down
}
if (event.keyCode == 37) {
x -= speed; //going left
}
if (event.keyCode == 39) {
x += speed; //going right
}
render();
}
function render() {
// context.clearRect(0, 0, canvas.width, canvas.height);
context.drawImage(playerimage, x, y, width, height);
}
</script>
</head>
<body onload="init();">
<button onclick="init();">Draw</button>
<canvas id="Mycanvas" width="550" height="400"></canvas>
</body>
</html>
JavaScript控制台总是给我的画布是空的错误
BTW,用分号(';'),而不是用逗号(',')来分隔javascript中的命令。 –
@PetrR。 - 不在声明多个变量的多行var语句中。 – nnnnnn
@nnnnnn - 我没有意识到这一点。我的错。 –