update (after considering your comment and new sketch)
Take a look at:
html:
<div class="container">
<div class="row">
<div class="col-sm-9" style="background-color:lightgreen;height:500px;">
Content
<button id="navigator">Show Nav</button>
</div>
<div class="sidenav col-sm-3" style="background-color:red;height:100px;">Nav</div>
</div>
<hr>
<footer>
<p>© Company 2013</p>
</footer>
</div><!--/.container-->
css:
@media (max-width: 767px)
{
.sidenav
{
position: absolute;
top: 50px;
height: 0px;
width: 0px;
overflow: hidden;
left:100%;
padding:0;
}
.sidenav.on
{
width:50%;
left:50%;
-webkit-transition: all 2s ease 0s;
-moz-transition: all 2s ease 0s;
-o-transition: all 2s ease 0s;
transition: all 2s ease 0s;
}
}
javascript:
$('#navigator').click(function(){$('div.sidenav').toggleClass('on');});
--
Indeed, check out:
The off canvas feature is not a standard element of bootstrap.
This demonstration illustrates the capabilities of Bootstrap, css, mediaqueries, and javascript (jQuery).
1) Media queries hide the sidebar when the screen width is under 768px (css with negative right position)
2) Clicking the button adds the class .active to the content (including the sidebar)
3) Css positions the content with class .active to the left with ...% (positive right position), hiding the content (outside the viewport) and revealing the navbar.
4) The show/hide effect is achieved using CSS3 transitions http://www.w3schools.com/css3/css3_transitions.asp
In the original example, if you change the content's width from 50% to 100% (or slightly more), it will create an overlap effect.
You may also want to refer to:
Toggle sidebar on mobile device with Twitter Bootstrap 2.x (can be easily adapted for TB3)