function doLarger(maxSize) {
  var newSize;
  newSize=parseInt(document.getElementById('tiger').style.height)+10;
  if(newSize>maxSize){
    document.getElementById('tiger').style.height=maxSize+'px';
  }else{
    document.getElementById('tiger').style.height=newSize+'px';
    setTimeout("doLarger("+maxSize+")",10);
  }
}