WTF Javascript?

I stumbled over this code..

javascript:R=0; x1=.1; y1=.05; x2=.25; y2=.24; x3=1.6; y3=.24; x4=300; y4=200; x5=300; y5=200; DI=document.images; DIL=DI.length; function A(){for(i=0; i-DIL; i++){DIS=DI[ i ].style; DIS.position='absolute'; DIS.left=Math.sin(R*x1+i*x2+x3)*x4+x5;*y1+i*y2+y3)*y4+y5}R++}setInterval('A()',5); void(0);

Go to

Copy the above javascript and paste it into your title bar, hit enter.

Watch the google logo fly.

Should you really be able to enter Javascript into the URL?