var roundedCorner = function(){
  $$('.rounded').each(function(el){
    
    el.set('styles', {
      'position': 'relative'
    });
    
    var divs = [];
  	divs[0] = new Element('div', {
  		'class': 'rounded_corner_tl'
  	});
  	divs[1] = new Element('div', {
  		'class': 'rounded_corner_tr'
  	});
  	divs[2] = new Element('div', {
  		'class': 'rounded_corner_bl'
  	});
  	divs[3] = new Element('div', {
  		'class': 'rounded_corner_br'
  	});
  	$$(divs).inject(el, 'top');
  });
}

window.addEvent('domready', roundedCorner);