感情都在代码里，来，干了！...
<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>贪吃蛇</title>
<style type="text/css">
*{
margin:0;
padding: 0;
}
#box{
height: 400px;
600px;
margin:50px auto;
border:1px solid #ccc;
position: relative;
}
.snake{
height: 18px;
18px;
background: red;
position: absolute;
border:1px solid #ccc;
top: 0;
left: 0;
}
.con{
height: 20px;
20px;
background: green;
position: absolute;
top: 60px;
left: 80px;
}
</style>
</head>
<body>
<div id="box">
<div class="snake"></div>
<p class="con"></p>
</div>
</body>
<script type="text/javascript">
var box=document.getElementById('box');
var snake=box.getElementsByClassName('snake');
var l=0,t=0,time=null;
var s=false,x=false,z=false,y=true;
function test () {
//获取box各个方向的距离
var l1=snake[0].offsetLeft;
var r1=snake[0].offsetLeft+snake[0].offsetWidth;
var t1=snake[0].offsetTop;
var b1=snake[0].offsetTop+snake[0].offsetHeight;
//获取con各个方向的距离
var con=box.getElementsByClassName('con')[0];
var l2=con.offsetLeft;
var r2=con.offsetLeft+con.offsetWidth;
var t2=con.offsetTop;
var b2=con.offsetTop+con.offsetHeight;
var a,b,c,d;
var f1;
// if (l1>=r2||r1<=l2||t1>=b2||b1<=t2) {
// a=false;
// } else{
// a=true;
// }
// return a;
if (z&&l1<=r2&&!(r1<=l2||t1>=b2||b1<=t2)) {
a=true;
} else{
a=false
};
if (y&&r1>=l2&&!(l1>=r2||t1>=b2||b1<=t2)) {
b=true;
} else{
b=false
};
if (s&&t1<=b2&&!(l1>=r2||r1<=l2||b1<=t2)) {
c=true;
} else{
c=false
};
if (x&&b1>=t2&&!(l1>=r2||r1<=l2||t1>=b2)) {
d=true;
} else{
d=false
};
return(a||b||c||d);
};
//创建食物
function creat () {
var flag=false;
do{
var left=parseInt(Math.random()*30)*20;
var top=parseInt(Math.random()*20)*20;
for (var i = 0; i < snake.length; i++) {
if (snake[i].offsetLeft==left&&snake[i].offsetTop==top) {
flag=true;
break;
} else{
flag=false;
}
};
}while(flag);
var newp=document.createElement('p');
newp.className='con';
newp.style.left=left+'px';
newp.style.top=top+'px';
box.appendChild(newp);
}
//判断游戏结束
function gameOver (zuo,shang) {
if (zuo<0||zuo>=600||shang<0||shang>=400) {
clearInterval(time);
alert('game over!点击确定后按“F5”重新开始游戏');
f1=false;
};
for (var i = 1; i < snake.length; i++) {
if(snake[i].offsetLeft==zuo&&snake[i].offsetTop==shang){
clearInterval(time);
alert('game over!');
f1=false;
};
};
}
function insert (obj1,obj2,left,top) {
obj1.style.top=top+'px';
obj1.style.left=left+'px';
obj2.insertBefore(obj1,snake[0]);
}
function remove (obj,name,num) {
var con=obj.getElementsByClassName(name)[num];
obj.removeChild(con);
}
function getlong (obj,obj1,name,left,top,num) {
f1=true;
gameOver(left,top);
if (f1) {
insert (obj1,obj,left,top);
remove (obj,name,num);
creat();
};
}
function move (obj,obj1,name,left,top,num,name1) {
f1=true;
gameOver(left,top);
if (f1) {
insert (obj1,obj,left,top);
obj.removeChild(name1[name1.length-1]);
};
}
time=setInterval(function () {
var Nsnake=document.createElement('div');
Nsnake.className='snake';
var ll=snake[0].offsetLeft;
var tt=snake[0].offsetTop;
var flag=true;
if(x){
if(test()){
tt+=20;
getlong (box,Nsnake,'con',ll,tt,0);
}else{
tt+=20;
move (box,Nsnake,'con',ll,tt,0,snake);
}
}
if(y){
if(test()){
ll+=20;
getlong (box,Nsnake,'con',ll,tt,0);
}else{
ll=ll+20;
move (box,Nsnake,'con',ll,tt,0,snake);
}
}
if(s){
if(test()){
tt-=20;
getlong (box,Nsnake,'con',ll,tt,0);
}else{
tt-=20;
move (box,Nsnake,'con',ll,tt,0,snake);
}
}
if(z){
if(test()){
ll-=20;
getlong (box,Nsnake,'con',ll,tt,0);
}else{
ll-=20;
move (box,Nsnake,'con',ll,tt,0,snake);
}
}
},150)
document.onkeydown=function (ev) {
var e=ev||window.event;
var time1,time2,tim3,time4;
function clear () {
clearTimeout(time1);
clearTimeout(time2);
clearTimeout(time3);
clearTimeout(time4);
}
switch(e.keyCode){
case 37:
if (y) {
z=false;
y=true;
s=false;
x=false;
} else{
time1=setTimeout(function () {
z=true;
y=false;
s=false;
x=false;
},50)
};
break;
case 38:
if (x) {
z=false;
y=false;
s=false;
x=true;
} else{
time2=setTimeout(function () {
z=false;
y=false;
s=true;
x=false;
},50)
};
break;
case 39:
if (z) {
z=true;
y=false;
s=false;
x=false;
} else{
time3=setTimeout(function () {
z=false;
y=true;
s=false;
x=false;
},50)
};
break;
case 40:
if (s) {
z=false;
y=false;
s=true;
x=false;
} else{
time4=setTimeout(function () {
z=false;
y=false;
s=false;
x=true;
},50)
};
break;
}
}
</script>
</html>