javascript制作贪吃蛇游戏_Javascript教程_H5之家 - 中国HTML5教程资源分享第一站

1、IE: element.innerText = FF: element.textContent；
2、setAttribute("cellpadding","0")在IE中无效，正确写法cellPadding (一不小心就犯错了)；
3、FF中，使用绑定在某元素上的键盘事件前，先让它获得焦点，document也不例外，这容易疏忽；
4、在IE中create table element，记得加tbody；
5、画面每渲染一次只有一次方向键有效，注意程序中的变量 allowPress （修复#2、#4、#5提到的问题）；

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>贪吃蛇 - by CNwander</title>
<style type="text/css">
* {margin:0; padding:0}
body {background:#333; -moz-user-select:none; text-align:center; font-size:12px}
table {margin:80px auto 10px auto; overflow:hidden; border-collapse:collapse; }
td {width:20px; height:20px; border:1px solid #eee; background:#f4f4f4}
.cover {background:#39c;}
.food {background:#093}
.block {background:#333}
.brake {background:#f00}
.skate {background:#00f}
#say {margin-top:50px; color:white}
#help {width:420px; margin:0 auto; line-height:17px; color:white}
#help span {float:left; margin-right:10px}
#help .box {width:15px; height:15px; margin-right:5px; border:1px solid white}
#btnStart {clear:both; width:100px; height:30px; margin-top:10px; padding:0; background:#bbb; color:#222; border:1px solid #fff; border-bottom-color:#000; border-right-color:#000; cursor:pointer}
</style>
<script type="text/javascript">
// code by CNwander.
// common
function $(str) {
return document.getElementById(str);
}
function ../tag/tag_Javascript.html(str,target) {
target = target || document;
return target.getElementsByTagName(str);
}
// global
// const
var WIDTH = 20, //网格宽度
HEIGHT = 20, //网格高度
SAY = ["相当不错，虽然说和CNwander还不是一个级别的","可以啊，再加点油都可以和CNwander媲美了！","一个字，牛，连CNwander都甘拜下风了","差不多行了，别把游戏玩爆了"];
var len = 3, //蛇的长度
speed, //爬行速度
gridElems = multiArray(WIDTH,HEIGHT), //单元格对象
carrier, //承载对象(食物，障碍，滑板，刹车)
snake, //蛇每节的坐标点
info, //交互对话
btnStart, //开始按钮
topScore = len,
snakeTimer, //蛇行走计时器
brakeTimers = [], //随机刹车
skateTimers = [], //随机滑板
directkey, // 方向键值 37-40 左上右下
allowPress = true;
window.onload = function(){
info = $("say");
btnStart = $("btnStart");
initGrid(); //网格初始化
document.onkeydown = attachEvents; //绑定方向事件
btnStart.onclick = function (e) {
  btnStart.blur(); //firefox中必须释放焦点
  start(); //游戏开始
  btnStart.setAttribute("disabled",true);
  btnStart.style.color = "#aaa";
}
}
//开始游戏
function start() {
len = 3;
speed = 10;
directkey = 39;
carrier = multiArray(WIDTH,HEIGHT);
snake = new Array();
clear();
initSnake(); //蛇初始化
addObject("food");
walk();
addRandomBrake();
}
//创建网格
function initGrid() {
var body = ../tag/tag_Javascript.html("body")[0];
var table = document.createElement("table"),
  tbody = document.createElement("tbody")
for(var j = 0; j < HEIGHT; j++) {
  var col = document.createElement("tr");
  for(var i = 0; i < WIDTH; i++) {
   var row = document.createElement("td");
   gridElems[i][j] = col.appendChild(row);
  }
  tbody.appendChild(col);
}
table.appendChild(tbody);
$("snakeWrap").appendChild(table);
}
//创建蛇
function initSnake() {
var pointer = randomPointer(len-1, len-1, WIDTH/2);
for(var i = 0; i < len; i++) {
  var x = pointer[0] - i,
   y = pointer[1];
  snake.push([x,y]);
  carrier[x][y] = "cover";
}
}
//添加键盘事件
function attachEvents(e) {
e = e || event;
if( allowPress )
directkey = Math.abs(e.keyCode - directkey) != 2 && e.keyCode > 36 && e.keyCode < 41 ? e.keyCode : directkey; //非方向键、反向无效
allowPress = false;
return false;
}
function walk() {
if(snakeTimer) window.clearInterval(snakeTimer);
snakeTimer = window.setInterval(step, Math.floor(3000/speed));
}
function step() {
//获取目标点
var headX = snake[0][0],
  headY = snake[0][1];
switch(directkey) {
  case 37: headX -= 1; break;
  case 38: headY -= 1; break;
  case 39: headX += 1; break
  case 40: headY += 1; break;
}
//碰到边界，阻挡物，则结束游戏
if(headX >= WIDTH || headX < 0 || headY >= HEIGHT || headY < 0 || carrier[headX][headY] == "block" || carrier[headX][headY] == "cover" ) {
  trace("GAME OVER");
  if(getText($("score"))*1 < len) trace(len,$("score"));
  btnStart.removeAttribute("disabled");
  btnStart.style.color = "#000";
  window.clearInterval(snakeTimer);
  for(var i = 0; i < brakeTimers.length; i++) window.clearTimeout(brakeTimers[i]);
  for(var i = 0; i < skateTimers.length; i++) window.clearTimeout(skateTimers[i]);
  return;
}
//加速
if(len % 4 == 0 && speed < 60 && carrier[headX][headY] == "food") {
  speed += 5;
  walk();
  trace("加速！");
}
//捡到刹车
if(carrier[headX][headY] == "brake") {
  speed = 5;
  walk();
  trace("恭喜！捡到刹车一个。");
}
//遭遇滑板
if(carrier[headX][headY] == "skate") {
  speed += 20;
  walk();
  trace("遭遇滑板！");
}
//添加阻挡物
if(len % 6 == 0 && len < 60 && carrier[headX][headY] == "food") {
  addObject("block");
}
//对话
if(len <= 40 && len % 10 == 0) {
  var cheer = SAY[len/10-1];
  trace(cheer);
}
//吃东西
if(carrier[headX][headY] != "food") {
  var lastX = snake[snake.length-1][0],
   lastY = snake[snake.length-1][1];
  carrier[lastX][lastY] = false;
  gridElems[lastX][lastY].className = "";
  snake.pop();
} else {
  carrier[headX][headY] = false;
  trace("吃到食物");
  addObject("food");
}
snake.unshift([headX,headY]);
carrier[headX][headY] = "cover";
gridElems[headX][headY].className = "cover";

len = snake.length;
allowPress = true;
}
//添加物品
function addObject(name) {
var p = randomPointer();
carrier[p[0]][p[1]] = name;
gridElems[p[0]][p[1]].className = name;
}
//添加随机数量刹车和滑板
function addRandomBrake() {
var num = randowNum(1,5);
for(var i = 0; i < num; i++) {
  brakeTimers.push( window.setTimeout(function(){addObject("brake")},randowNum(10000,100000)) );
  skateTimers.push( window.setTimeout(function(){addObject("skate")},randowNum(5000,100000)) );
}
}
//输出信息
function trace(sth,who) {
who = who || info;
if(document.all) who.innerText = sth;
else who.textContent = sth;
}
//获取信息
function getText(target) {
if(document.all) return target.innerText;
else return target.textContent;
}
//创建二维数组
function multiArray(m,n) {
var arr = new Array(n);
for(var i=0; i<m; i++)
  arr[i] = new Array(m);
return arr;
}
//清除画面
function clear() {
for(var y = 0; y < gridElems.length; y++) {
  for(var x = 0; x < gridElems[y].length; x++) {
   gridElems[x][y].className = "";
  }
}
}
//产生指定范围随机点
function randomPointer(startX,startY,endX,endY) {
startX = startX || 0;
startY = startY || 0;
endX = endX || WIDTH;
endY = endY || HEIGHT;
var p = [],
  x = Math.floor(Math.random()*(endX - startX)) + startX,
  y = Math.floor(Math.random()*(endY - startY)) + startY;
if(carrier[x][y]) return randomPointer(startX,startY,endX,endY);
p[0] = x;
p[1] = y;
return p;
}
//产生随机整数
function randowNum(start,end) {
return Math.floor(Math.random()*(end - start)) + start;
}
</script>
</head>
<body onselectstart="return false">
<div id="say">贪吃蛇</div>
    <div id="snakeWrap"></div>
    <div id="help">
    <span class="box food"></span><span>绿色食物</span>
        <span class="box block"></span><span>灰色毒品</span>
        <span class="box skate"></span><span>蓝色滑板</span>
        <span class="box brake"></span><span>红色刹车</span>
        <span style="float:right">最高分：<strong id="score">0</strong></span>
        <input type="button" id="btnStart" value="开始游戏" />
    </div>
</body>
</html>