Fixed Element Overflow - css

Question

I'm trying to get the #sidebar element to scroll overflow once the browser window is shorter than it's minimum height but can't seem to get it working. Any idea why?
http://jsfiddle.net/q5jKM/1/
CSS - Sorry I cant get this funky formatting working.
html,body{height:100%;margin:0}
#sidebar {
width: 20em;
position:fixed;
top: 0;
bottom: 0;
left: 0;
z-index:2;
color: #ffffff;
background-color: #333333;
overflow:auto;
min-height: 34em;
}
#sidebar .nav {
width: 3em;
float: right;
overflow: auto;
background-color: #2e2e2e;
border-left: 2px groove #454545;
height: 100%;
position:relative;
}
#sidebar .content {
height: 100%;
width: 16.875em; /* 17-(2/16) - 20em - .nav - nav border*/
float:left;
position:relative;
}
#sidebar .top {
position:absolute;
top:0;
}
#sidebar .bottom {
position:absolute;
bottom:0;
}
#sidebar .middle {
position: absolute;
bottom: 12em; /* 3.125*3 */
top: 16em; /* 3.125*4 */
background: green;
}
.content .middle {
overflow:auto;
}
#sidebar .content > div {width: 16.875em; } /*.top .middle .bottom*/
#sidebar .nav > div {width:3em; } /*.top .middle .bottom*/
/*table-cell trying get vertical-align working*/
#sidebar .table-cell {display:table-cell;}
#sidebar .middle .table-cell {vertical-align: middle;}
#sidebar .content p, #sidebar .content li, #sidebar .content img {font-size: .75em; color: #dddddd;}
#sidebar ul {margin:0; padding: 0;}
#sidebar .nav li {
padding: .5625em;
list-style:none;
}
#sidebar .nav li img {
height: 1.875em;
width: 1.875em
}
#sidebar .nav .top li { border-bottom: 2px groove #454545 }
#sidebar .nav .bottom li { border-top: 2px groove #454545 }
.content li {
position:relative;
display:block;
background-color: #444;
padding: .72em;
border-radius: .8em;
border-bottom: 1px solid #292929;
border-top: 1px solid #4c4c4c;
text-align: center;
font-size: 1em;
letter-spacing: .1em;
font-weight: normal;
height: 1.2em;
}
.content li:after {
content:"";
position:absolute;
display:block;
width:0;
top:.11em; /* controls vertical position */
right:-.852em; /* value = - border-left-width - border-right-width */
border-style:solid;
border-width:1.2em 0 1.2em 1.2em;
border-color:transparent #444;
}
.content .top li{margin: .95em 0 1.9em 0;}
.content .bottom li{margin: 1.9em 0 .95em 0;}
.content .logo {
text-align: center;
padding: 1em 0 2em 0;
width: 100%;
border-bottom: 2px groove #454545;
}
.content p.welcome {
text-align: center;
line-height: 1.5em;
margin: 1em 0;
}
HTML
<div id="sidebar">
<div class="nav">
<div class="top">
<ul>
<li><img src="_images/attributes/attribute2.svg"></li>
<li><img src="_images/attributes/attribute2.svg"></li>
<li><img src="_images/attributes/attribute2.svg"></li>
<li><img src="_images/attributes/attribute2.svg"></li>
</ul>
</div>
<div class="middle"><div class="table-cell"><p>test</p></div></div>
<div class="bottom">
<ul>
<li><img src="_images/attributes/attribute2.svg"></li>
<li><img src="_images/attributes/attribute2.svg"></li>
<li><img src="_images/attributes/attribute2.svg"></li>
</ul>
</div>
</div>
<div class="content">
<div class="top">
<ul>
<li>SIDEBAR LINK</li>
<li>SIDEBAR LINK</li>
<li>SIDEBAR LINK</li>
<li>SIDEBAR LINK</li>
</ul>
</div>
<div class="middle"><div class="table-cell">
<div class="logo"><img src="_images/g.svg"></div>
<p class="welcome">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris dictum tellus viverra neque bibendum in mattis ante dignissim. Nam mattis feugiat lorem porttitor adipiscing. Aliquam erat volutpat. Nunc feugiat magna vitae mauris egestas euismod. In hac habitasse platea dictumst. Praesent magna sem, malesuada non fermentum vel, luctus quis mauris. Duis quam purus, ornare vitae eleifend sed, malesuada eget libero. Phasellus sed lorem risus, nec placerat urna. In magna turpis, accumsan ac egestas quis, dictum vel massa. Nulla vitae magna arcu. Maecenas sit amet vestibulum urna. Integer feugiat dignissim leo sed ornare. Maecenas auctor ultricies dui, pulvinar tincidunt velit feugiat quis. Sed egestas ornare elit, et fringilla quam viverra ut.</p>
</div></div>
<div class="bottom">
<ul>
<li>SIDEBAR LINK</li>
<li>SIDEBAR LINK</li>
<li>SIDEBAR LINK</li>
</ul>
</div>
</div>
</div>

Answer 1

Got it!
Add: - So that #sidebar's is equal to the browser window.
#sidebar{height:100%}
And add: - To provide content that overflows.
#sidebar .nav, #sidebar .content {min-height:34em}
Once the browser window becomes shorter than 34ems #sidebar will overflow.

Answer 2

You just need to add a CSS media query rule:
#media all and (min-height: 34em) {
#sidebar{
overflow: scroll;
}
}
Once the browser height is less than 34em, then the overflow: scroll rule will be added to the #sidebar.

Answer 3

Use overflow scroll instead of auto
See this http://jsfiddle.net/q5jKM/2/

Answer 4

I got this to work using jquery - you need to get the height of the browser and adjust the css overflow to scroll when it reaches a certain height
var heightToScroll = 600;
var viewHeight = $(window).height();
$(window).resize(function() {
if(viewHeight < heightToScroll){
$('#sidebar').css("overflow","scroll");
}
});
http://jsfiddle.net/q5jKM/3/