我写了一个javascript代码在点击画布时多次放入球。这是一个实验。
下面是代码:
HTML
使用Javascript时出错的错误
<br style="clear: both" />
<canvas id="myCanvas1" width="134px" height="331px" onclick="draw(0)"></canvas>
<canvas id="myCanvas2" width="134px" height="331px" onclick="draw(1)"></canvas>
<canvas id="myCanvas3" width="134px" height="331px" onclick="draw(2)"></canvas>
JAVASCRIPT
var balls = [[], [], []],
canvases = document.getElementsByTagName('canvas'),
context = [],
interval,
boxWidth = 150,
ballRadius = 10,
canvasHeight = 235;
for (var i = 0; i < canvases.length; i++) {
context.push(canvases[i].getContext('2d'));
}
function draw() {
var movement = false;
for (var i = 0; i < 3; i++) {
context[i].clearRect(0, 0, boxWidth, canvasHeight);
for (var j = 0; j < balls[i].length; j++) {
if (balls[i][j].y < balls[i][j].yStop) {
balls[i][j].y += 4;
movement = true;
}
context[i].beginPath();
context[i].fillStyle = "red";
context[i].arc(balls[i][j].x, balls[i][j].y, ballRadius, 0, Math.PI * 2, true);
context[i].closePath();
context[i].fill();
}
}
if (!movement) {
clearInterval(interval);
interval = null;
}
}
function newBall(n) {
console.log('new ball', n);
var last = balls[n][balls[n].length - 1],
ball = {x: ballRadius, y: ballRadius, yStop: canvasHeight - ballRadius};
if (last) {
if (last.x < boxWidth - ballRadius * 3) {
ball.x = last.x + ballRadius * 2;
ball.yStop = last.yStop;
} else {
ball.yStop = last.yStop - ballRadius * 2;
}
}
balls[n].push(ball);
if (!interval) {
interval = setInterval(draw, 10);
}
}
但球没有下降的请告诉我,我在哪里错了,这样我可以修复它...
这个问题的标题是这样的史诗:d,直到你来到这里,实际上读它:P – ProllyGeek 2014-11-02 20:36:41
我必须设置一个史诗般的标题,以便它可以引诱人;) – qwertymaster 2014-11-02 20:44:48
投票了这个问题,这样我可以标记的问题作为完成 – qwertymaster 2014-11-02 20:58:38