JS1k: The JavaScript code golfing competition

var d=document,c=d.getElementById("c"),w=window,v=300,b=211,n=m=x=100,j=k=q=10,f=c.getContext("2d");f.r=f.fillRect;$=function(x,y,w,t){if(t)f.r(x,y,w,q);else f.clearRect(x,y,w,q)};g=function(x,y){return f.getImageData(0,0,b,310).data[(x+y*b)*4]};c.width=211;c.height=311;f.fillStyle="rgb(1,1,1)";f.r(0,0,b,60);i=w.setInterval(function(){$(n,m,q,0);f.strokeRect(0,0,b,311);j=n<q||n>190?j*-1:j;if(m<q||m>290||g(n,m+q)||g(n,m-1)){k*=-1;if(g(n,m-1))$(n,m-q,q,0)}n+=j;m+=k;$(n,m,q,1);$(x,v,40,1);if(m==v){w.clearInterval(i);f.fillText("END",90,b)}},n);d.addEventListener("keyup",function(k){$(x,v,40,0);x=k.keyCode==37&&x>0?x-q:k.keyCode==39&&x<170?x+q:x;$(x,v,40,1)},0);

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