$(document).ready(function() {
	$('a[id^=a_]').click(function() {
		var the_id = $(this).attr('id');
		var name = the_id.split('_')[1];
		close_all();
		show_the(name);
		return false;
	});

	function close_all()
	{
		$('div[id^=content_]').hide();
	}

	function show_the(name)
	{
		$('a[id^=a_]').css('color', '#999');
		$('a#a_'+name).attr("disabled","disabled");
		$('a#a_'+name).css('color', 'black');
		$('div#content_'+name).show();
	}
});