// moveImage function

function moveImage(elementID,finalx,finaly,interval) {
  if (!document.getElementById) return false;
  if (!document.getElementById(elementID)) return false;
  var elem = document.getElementById(elementID);
  if (elem.movement) {
    clearTimeout(elem.movement);
  }

  var x_pos = parseInt(elem.style.left);
  var y_pos = parseInt(elem.style.top);

  if (x_pos == finalx && y_pos == finaly) {
    return true;
  }
  if (x_pos < finalx) {
    var dist = Math.ceil((finalx - x_pos)/10);
    x_pos = x_pos + dist;
  }
  // if x_pos is greater than finalx, then the traveled distance of "slideart"
  // is calculated by subtracting finalx from x_pos, which is divided by 10
  // the ceil property rounds any floating-point number up to the nearest integer
  if (x_pos > finalx) {
    var dist = Math.ceil((x_pos - finalx)/10);
    x_pos = x_pos - dist;
  }
  if (y_pos < finaly) {
    var dist = Math.ceil((finaly - y_pos)/10);
    y_pos = y_pos + dist;
  }
  if (y_pos > finaly) {
    var dist = Math.ceil((y_pos - finaly)/10);
    y_pos = y_pos - dist;
  }
  elem.style.left = x_pos + "px";
  elem.style.top = y_pos + "px";
  var repeat = "moveImage('"+elementID+"',"+finalx+","+finaly+","+interval+")";
  elem.movement = setTimeout(repeat,interval);
}