كود نجوم تتحرك مع الخلفية

<SCRIPT type=text/javascript>
        // <![CDATA[
        var colour="silver";
        var sparkles=70;
        /****************************
        *  Tinkerbell Magic Sparkle *
        * (c) 2008 *
        * http://www.mundopixel.org *
        * DON'T EDIT BELOW THIS BOX *
        ****************************/
        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=rats);
            starv=0;
            tinyv=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=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==25) star.style.clip="rect(1px, 4px, 4px, 1px)";
          if (starv) {
            stary+=1+Math.random()*3;
            if (stary<shigh+sdown) {
              star.style.top=stary+"px";
              starx+=(i%5-2)/5;
              star.style.left=starx+"px";
            }
            else {
              star.style.visibility="hidden";
              starv=0;
              return;
            }
          }
          else {
            tinyv=50;
            tiny.style.top=(tinyy=stary)+"px";
            tiny.style.left=(tinyx=starx)+"px";
            tiny.style.width="2px";
            tiny.style.height="2px";
            star.style.visibility="hidden";
            tiny.style.visibility="visible"
          }
        }
        function update_tiny(i) {
          if (--tinyv==25) {
            tiny.style.width="1px";
            tiny.style.height="1px";
          }
          if (tinyv) {
            tinyy+=1+Math.random()*3;
            if (tinyy<shigh+sdown) {
              tiny.style.top=tinyy+"px";
              tinyx+=(i%5-2)/5;
              tiny.style.left=tinyx+"px";
            }
            else {
              tiny.style.visibility="hidden";
              tinyv=0;
              return;
            }
          }
          else tiny.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>