$(function() {
$("#show-background").click(function () {
$("#content-area").animate({opacity: 'toggle'}, 'slow');
});
var text = $('#show-background').text();
$('#show-background').text(
text == "Show Background" ? "Show Text" : "Show Background");
});
Toggle hides or shows elements. You could achieve the same effect using toggle by having 2 links and toggling them when either is clicked.