<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8">
<style>
ul{
margin:0 auto;
width:600px;
}
li{
border-radius:10px;
box-sizing:border-box;
list-style:none;
float:left;
width:30px;
height:30px;
border:1px solid #6495ED;
}
.snake{
background-color:black;
}
.food{
background-color:red;
}
.headSnake{
background-color:green
}
</style>
</head>
<body>
<ul></ul>
</body>
<script>
//50X50格子，用二位数组取
var deskArr = [];
//创建文档片段
var fragment = document.createDocumentFragment() ;
for(var i=0;i<20;i++){
var rowArr = [];
for(var j=0;j<20;j++){
var li = document.createElement("li");
fragment.appendChild(li);
rowArr.push(li);
}
deskArr.push(rowArr);
}
document.querySelector("ul").appendChild(fragment);
//蛇数组
var snake = [];
//分数
var score = 0;
//蛇头1-18
var headNumX = parseInt(Math.random()*(17)+1);
//蛇头0-19
var headNumY = parseInt(Math.random()*19);
//改变蛇头的颜色
snake.push(deskArr[headNumY][headNumX]);
snake.push(deskArr[headNumY][headNumX-1]);
snake[0].className = "headSnake";
snake[1].className = "snake";
//console.log(snake);
//蛇移动
//蛇移动的速度
var speed = 500;
//蛇移动的默认方向
var dir = "right";
//是否showFood
var food = 1;
//吃到食物的标志
var foodFlag = false;
function snakeMove(){
if(food==1){
foodShow();
food=0;
}
/*键盘事件
当向上键并且默认方向不是下时，dir="up"
当向下键时，dir="down"
当向左键时，dir="left"
当向右键时，dir="right"
*/
document.onkeydown = function(){
var event= window.event||arguments[0];
if(event.keyCode==37&&dir!="right"){
dir = "left";
}else if(event.keyCode == 38&&dir!="down"){
dir = "up";
}else if(event.keyCode == 40&&dir!="up"){
dir = "down";
}else if(event.keyCode == 39&&dir!="left"){
dir = "right";
}
}
//方向判断
switch (dir)
{
case "right":
headNumX++;
break;
case "left":
headNumX--;
break;
case "up":
headNumY--;
break;
case "down":
headNumY++;
break;
}
snake[snake.length-1].className = "";
snake.pop();
snake[0].className="snake";
snake.unshift(deskArr[headNumY][headNumX]);
snake[0].className = "headSnake";
//判断是否吃到食物
if(snake[0]==deskArr[foodY][foodX]){
snake[0].className="snake";
if(dir =="up"){
headNumY--;
}else if(dir =="down"){
headNumY++;
}else if(dir =="left"){
headNumX--;
}else if(dir =="right"){
headNumX++;
}
snake.unshift(deskArr[headNumY][headNumX]);
snake[0].className="headSnake";
score++;
foodShow();
}
liveOrDie()&&(setTimeout(snakeMove,speed));
}
setTimeout(snakeMove,speed)
//随机生成一个食物
/*
随机生成foodX，foodY
0-19 0-19
判断该位置是否与身体重合
若重合，则重新取值
若不重合，则显示food
*/
var foodX;
var foodY;
function foodShow(){
foodX = parseInt(Math.random()*17+1);
foodY = parseInt(Math.random()*17+1);
var flag = 0;
for(var i=0;i<snake.length;i++){
(snake[i]==deskArr[foodY][foodX])&&(flag=1);
}
!flag?
deskArr[foodY][foodX].className = "food"
:foodShow();
}
/*判断是否游戏失败
1.撞墙
头的坐标Y 小于0或者大于19
头的坐标X 小于0或者大于19
2.撞到自己的身体
循环，当两个对象一样时，
*/
function liveOrDie(){
console.log(headNumX);
if(headNumX>19||headNumX<0||headNumY>19||headNumY<0){
alert("游戏结束"+"\n"+"最终得分"+score);
return 0 ;
}
for(var i=1;i<snake.length;i++){
if(snake[0]==snake[i]){
alert("游戏结束"+"\n"+"最终得分"+score);
return 0;
}
}
return 1;
}
</script>
</html>