$(document).ready(function(){
		lastBlock = $("#a1");
		maxWidth = 556;
		minWidth = 50;	
	
		$("#DeroulExpert ul li a").click(
		  function(){
			$(lastBlock).animate({width: minWidth+"px"}, { queue:false, duration:400 });
			$(this).animate({width: maxWidth+"px"}, { queue:false, duration:400});
			lastBlock = this;
		  }
		);
	});