var logged_in = false;
logged_in = !logged_in;
A little example:
var logged_in = false;_x000D_
_x000D_
_x000D_
$("#enable").click(function() {_x000D_
logged_in = !logged_in;_x000D_
checkLogin();_x000D_
});_x000D_
_x000D_
function checkLogin(){_x000D_
if (logged_in)_x000D_
$("#id_test").removeClass("test").addClass("test_hidde");_x000D_
else_x000D_
$("#id_test").removeClass("test_hidde").addClass("test");_x000D_
$("#id_test").text($("#id_test").text()+', '+logged_in);_x000D_
}
_x000D_
.test{_x000D_
color: red;_x000D_
font-size: 16px;_x000D_
width: 100000px_x000D_
}_x000D_
_x000D_
.test_hidde{_x000D_
color: #000;_x000D_
font-size: 26px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<div class="test" id="id_test">Some Content...</div>_x000D_
<div style="display: none" id="id_test">Some Other Content...</div>_x000D_
_x000D_
_x000D_
<div>_x000D_
<button id="enable">Edit</button>_x000D_
</div>
_x000D_