<script>
$(document).ready(function(){
    $('input[type="checkbox"]').click(function(){
        var inputValue = $(this).attr("id");
        $("." + inputValue).toggle();
    });
});
</script>

<input type="checkbox" name="mycheckbox" value="11" id="titletext" /> Click to display<br>

<div class="titletext" style="display: none;">
	Displayed text
</div>