var bShadowstart = false;
//var startx = 0;
var xoffset = 15;
var yoffset = 15;
var counter = 0;
var imgcnt = 0;
var numimg = 7;
var shadowx = new Array();
var shadowy = new Array();
var shadowcount = 6;
var timerid;
for (i=0; i<=shadowcount; i++) { shadowx[i] = -100; shadowy[i] = -100; }

function setShadowflag( bonoff ){
  bShadowstart = bonoff;
}

function calcStartx( pos_x ){
  startx = (pos_x / 2) + 450 + 10;
  return startx;
}

var shadowImgarray = new Array("../images/shadow1.gif","../images/shadow2.gif","../images/shadow3.gif","../images/shadow4.gif","../images/shadow5.gif","../images/shadow6.gif","../images/shadow7.gif");
var preImg = new Array();

function setShadowImg(){
  for ( i = 0; i<shadowImgarray.length; i++ )
  {
    preImg[i] = new Image();
    preImg[i].src = shadowImgarray[i];
  }
}

function setShadow(){

  shadowx[shadowcount] = event.x - xoffset;
  shadowy[shadowcount] = event.y - yoffset;

}

function setShadowTimer(){
  
  timerid = setInterval('moveShadow()',100);
  if( bShadowstart == false ){
    setShadowflag( true );
  }
}

function moveShadow(){
  
  var node;
  for( i=1; i<=shadowcount; i++ ){
    eval("document.shadow" + i + "img.src='" + shadowImgarray[(imgcnt+i)%numimg] + "'");
    shadowx[i-1] = shadowx[i];
    shadowy[i-1] = shadowy[i];
    node = document.getElementById( "shadow" + i );
    node.style.left= shadowx[i-1] + 'px';
    node.style.top = shadowy[i-1] + 'px';
  }
  
  if( counter > 10 ){
    counter = 0;
    ((imgcnt+1) > 1000) ? (imgcnt=0) : imgcnt++;
  }
  else{
    counter++;
  }
}

function clearShadow(){

  for( i=1; i<=shadowcount; i++ ){
    var node = document.getElementById( "shadow" + i );
    node.style.left= '-100px';
    node.style.top= '-100px';
  }
}

function hideShadow(){
  
  clearInterval( timerid );
  clearShadow();
  setShadowflag( false );
}