<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>弹弹球</title>
<script type="text/ecmascript">
var drawWorker;//重绘的事件
var result = 0;//整形，游戏坚持的时间，秒
var record = 0;//整形，游戏的记录
var timeWorker;//计时的事件，每秒一次 var pointRadius = 10;//球的半径
var pointX = 20;//球的圆心x坐标
var pointY = 20;//球的圆心y坐标 var speedX = 10;//球向右移动的速度
var speedY = 5;//球向下移动的速度 var panelX = 0;//小方块的最左边的x坐标
var panelY = 280;//小方块的最上端的y坐标
var panelHeight = 20;
var panelWidth = 100; var wholeWidth = 500;
var wholeHeight = 300; var canvas;
var ctx; function Init() {
canvas=document.getElementById("myCanvas");
ctx = canvas.getContext("2d"); ctx.strokeRect(0, 0, wholeWidth, wholeHeight);
} function DrawBall() {
var ctx = document.getElementById("myCanvas").getContext("2d"); ctx.clearRect(1, 1, wholeWidth-2, wholeHeight-2); //清理矩形范围 pointX = pointX + speedX;//新的圆心x坐标
pointY = pointY + speedY;//新的圆心y坐标 ctx.beginPath(); //弹弹球
ctx.arc(pointX, pointY, pointRadius, 0, Math.PI * 2);
ctx.closePath();
ctx.fill(); ctx.fillRect(panelX, panelY, panelWidth, panelHeight); //小方块
} function MoveBall() {
if (pointY >= wholeHeight - panelHeight) {
if (pointX < panelX || pointX > panelX + panelWidth) { EndGame(); //越过小方块，游戏结束
return;
}
else {
speedX = speedX > 0 ? speedX + 5 : speedX - 5; //碰到小方块，小球加速
speedY = speedY > 0 ? speedY + 5 : speedY - 5;
}
} if (pointX >= wholeWidth || pointX<=0) { //接触到边界，对应的方向转向
speedX = speedX - 2 * speedX;
} if (pointY >= wholeHeight - panelHeight || pointY <= 0) {
speedY = speedY - 2 * speedY;
} DrawBall(); } function MovePanel(event) {
panelX = event.pageX - (panelWidth / 2);
} function AddResult() {
result = result + 1;
var resultLabel = document.getElementById("currentLabel");
resultLabel.textContent = result;
} function Play() {
pointX =Math.floor( Math.random() * 20) + 10;//球的圆心x坐标
pointY = Math.floor(Math.random() * 20) + 10;//球的圆心y坐标 speedX = 20;//球向右移动的速度
speedY = 10;//球向下移动的速度 result = 0; drawWorker = setInterval(MoveBall, 100); //每100毫秒就重绘小球跟小方块位置
timeWorker = setInterval(AddResult, 1000); //每秒更新结果 canvas.addEventListener("mousemove", MovePanel, false); //开始玩，需要将所有相关参数都再初始化 } function EndGame() { //游戏结束
clearInterval(timeWorker); //停止两个定时任务
clearInterval(drawWorker); canvas.removeEventListener("mousemove", MovePanel, false); //移除鼠标移动事件的处理 if (result > record) {
record = result;
var recordLabel = document.getElementById("recordLabel");
recordLabel.textContent = result;
}
result = 0;
}
</script>
</head>
<body onload="Init();">
<canvas id="myCanvas" width="500" height="300">your broswer does not support canvas.</canvas>
<br />
<input type="button" value="play" onclick="Play();" />
<br />
<label>本次结果：</label>
<label id="currentLabel">0</label>
<br />
<label>最高纪录：</label>
<label id="recordLabel">0</label>
</body>
</html>
上文代码实现了一个很基本的弹弹球游戏。
按下Play按钮，在Canvas范围内左右移动鼠标，滑块会随之移动。如果成功接住落下的小球则小球加速并且变向。当小球落在底框的时候游戏结束。游戏将会记录坚持的时间。