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。