$(document).ready(function(){
    lastBlock = $("#a1");
    maxWidth = 503;
    minWidth = 63;	

    $("ul li div.barra").hover(
      function(){
		lastWidth =  $(lastBlock).children("img.barra").width();
		newWidth =  $(this).children("img.barra").width()+502;
       // $(lastBlock).animate({width: lastWidth+"px"}, { queue:false, duration:800 });
        $(lastBlock).animate({width: lastWidth+"px"}, { queue:false, duration:800 });
		$(this).animate({width: newWidth+"px"}, { queue:false, duration:800});
		lastBlock = this;
      }
    );
});