新建一个文本文件，将下列80行代码粘贴进去，重命名为.html, 用浏览器打开：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>snake</title>
<style type="text/css">
body { overflow:hidden; text-align:center; background-color:lavender; }
div#main { position:relative; overflow:hidden; margin:10px auto; border: 1px solid green; width:400px; height:400px; }
div#main div { position:absolute; font-size:0; background-color:green; width:10px; height:10px; }
div#main div#head { background-color:red; }
div#main div#food { background-color:green; }
</style>
</head>
<body>
<div id="main"><div id="head"></div><div id="food" style='visibility:hidden;'></div></div>
<script type="text/javascript">
var w=40, h=40, n=10, m=200;
var S={},X=[],B=[],L=[],T=[],dirs=[-1,-w,1,w],dir=2,ifood=-5,pause,f,timer,D=document;
function rnd(){return Math.floor(Math.random()*w*h)}
function newd(i){var div=main.appendChild(D.createElement("div"));p(div,i);return div;}
function p(o,i){o.style.left=L[i]+'px';o.style.top=T[i]+'px';}
function m(o,dir){p(o,i);}
function $(id){ return D.getElementById(id); }
function cli(){ clearInterval(tmr); }
function sei(m){ tmr=setInterval(Main,m); }
function Main(){
if(pause)return;
var ox=X[0],x=ox%w,y=(ox-x)/h,eat,die;
X[0]+=dirs[dir];
if(x==0&&dir==0||x==w-1&&dir==2||y==0&&dir==1||y==h-1&&dir==3)die='Died';
else if(S[X[0]])die='died';
if(die){
cli();
alert(die+'/n/ndied'+(B.length-1)+'died');
restart();
return;
}
if(ifood==X[0]){
eat=true;
food.style.visibility='hidden';
ifood=-5;
B.unshift(newd(ox));
}else if(ifood==-1){
while(S[ifood=rnd()]);
food.style.visibility='visible';
p(food,ifood);
}else if(ifood<-1){ifood++}
p(head,X[0]);
X.unshift(X[0]);
X[1]=ox;
S[X[0]]=true;
if(!eat){delete S[X.pop()];B.unshift(B.pop());p(B[0],ox);}
}
D.onkeydown=function(evt){
var c=(evt||window.event).keyCode-37;
if(c==-24)pause=!pause;
else if(c>=0&&c<4){
if(dir==c){if(!f){f=true;cli();sei(m/2)}}
else if(dir%2!=c%2)dir=c;
}
}
D.onkeyup=function(evt){
var c=(evt||window.event).keyCode-37;
if(dir==c&&f){f=false;cli();sei(m)}
}
for(var i=w*h-1;i>=0;i--){L[i]=i%w*n, T[i]=(i-i%w)*n/h}
var main=$("main"), head=$("head"), food=$("food");
function restart(){
S={},X=[],B=[],dir=2,ifood=-5,pause=f=false;
while(main.childNodes.length>2)main.removeChild(main.lastChild);
food.style.visibility='hidden';
X[1]=w*h/2;
X[0]=X[1]+1;
p(head,X[0]);
B[0]=newd(X[1]);
S[X[0]]=S[X[1]]=true;
sei(m);
}
restart();
</script>
</body>
</html> 
想当年这个游戏我能玩一下午：
代码第20行的变量m代表setInterval的第二个参数，单位是毫米，如果大家把默认的200毫秒改成20毫米再启动游戏，看看是不是来到了地狱难度。