The Head Tag
The head tag begins with this tag: <head> and ends with this tag: </head>. Go to Layout->Edit HTML.
Locate for end head tag (</head>) and paste your javascript code above it, then save.
The Code:
<script type="text/javascript"> // <![CDATA[ var colour="#666666"; var sparkles=40; var x=ox=400; var y=oy=300; var swide=800; var shigh=600; var sleft=sdown=0; var tiny=new Array(); var star=new Array(); var starv=new Array(); var starx=new Array(); var stary=new Array(); var tinyx=new Array(); var tinyy=new Array(); var tinyv=new Array(); window.onload=function() { if (document.getElementById) { var i, rats, rlef, rdow; for (var i=0; i<sparkles; i++) { var rats=createDiv(3, 3); rats.style.visibility="hidden"; document.body.appendChild(tiny[i]=rats); starv[i]=0; tinyv[i]=0; var rats=createDiv(5, 5); rats.style.backgroundColor="transparent"; rats.style.visibility="hidden"; var rlef=createDiv(1, 5); var rdow=createDiv(5, 1); rats.appendChild(rlef); rats.appendChild(rdow); rlef.style.top="2px"; rlef.style.left="0px"; rdow.style.top="0px"; rdow.style.left="2px"; document.body.appendChild(star[i]=rats); } set_width(); sparkle(); }} function sparkle() { var c; if (x!=ox || y!=oy) { ox=x; oy=y; for (c=0; c<sparkles; c++) if (!starv[c]) { star[c].style.left=(starx[c]=x)+"px"; star[c].style.top=(stary[c]=y)+"px"; star[c].style.clip="rect(0px, 5px, 5px, 0px)"; star[c].style.visibility="visible"; starv[c]=50; break; } } for (c=0; c<sparkles; c++) { if (starv[c]) update_star(c); if (tinyv[c]) update_tiny(c); } setTimeout("sparkle()", 40); } function update_star(i) { if (--starv[i]==25) star[i].style.clip="rect(1px, 4px, 4px, 1px)"; if (starv[i]) { stary[i]+=1+Math.random()*3; if (stary[i]<shigh+sdown) { star[i].style.top=stary[i]+"px"; starx[i]+=(i%5-2)/5; star[i].style.left=starx[i]+"px"; } else { star[i].style.visibility="hidden"; starv[i]=0; return; } } else { tinyv[i]=50; tiny[i].style.top=(tinyy[i]=stary[i])+"px"; tiny[i].style.left=(tinyx[i]=starx[i])+"px"; tiny[i].style.width="2px"; tiny[i].style.height="2px"; star[i].style.visibility="hidden"; tiny[i].style.visibility="visible" } } function update_tiny(i) { if (--tinyv[i]==25) { tiny[i].style.width="1px"; tiny[i].style.height="1px"; } if (tinyv[i]) { tinyy[i]+=1+Math.random()*3; if (tinyy[i]<shigh+sdown) { tiny[i].style.top=tinyy[i]+"px"; tinyx[i]+=(i%5-2)/5; tiny[i].style.left=tinyx[i]+"px"; } else { tiny[i].style.visibility="hidden"; tinyv[i]=0; return; } } else tiny[i].style.visibility="hidden"; } document.onmousemove=mouse; function mouse(e) { set_scroll(); y=(e)?e.pageY:event.y+sdown; x=(e)?e.pageX:event.x+sleft; } function set_scroll() { if (typeof(self.pageYOffset)=="number") { sdown=self.pageYOffset; sleft=self.pageXOffset; } else if (document.body.scrollTop || document.body.scrollLeft) { sdown=document.body.scrollTop; sleft=document.body.scrollLeft; } else if (document.documentElement && (document.documentElement.scrollTop || document.documentElement.scrollLeft)) { sleft=document.documentElement.scrollLeft; sdown=document.documentElement.scrollTop; } else { sdown=0; sleft=0; } } window.onresize=set_width; function set_width() { if (typeof(self.innerWidth)=="number") { swide=self.innerWidth; shigh=self.innerHeight; } else if (document.documentElement && document.documentElement.clientWidth) { swide=document.documentElement.clientWidth; shigh=document.documentElement.clientHeight; } else if (document.body.clientWidth) { swide=document.body.clientWidth; shigh=document.body.clientHeight; } } function createDiv(height, width) { var div=document.createElement("div"); div.style.position="absolute"; div.style.height=height+"px"; div.style.width=width+"px"; div.style.overflow="hidden"; div.style.backgroundColor=colour; return (div); } // ]]> </script>