How to get a Bootstrap dropdown submenu to 'dropup' - html

Question

I have a Bootstrap dropdown menu. The last li item is a submenu. How do I get the submenu to dropup while the full menu drops down? Here's the code:
<div class="dropdown">
<a class="inputBarA dropdown-toggle" data-toggle="dropdown" href="#">FILTER</a>
<ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
<li role="presentation">
<a role="menuitem" href="#">Text</a>
</li>
<li role="presentation">
<label>Label name</label>
<label>Label name</label>
<label class="checkbox">
<input type="checkbox">
Text </label>
<label class="checkbox">
<input type="checkbox">
Text </label>
<label class="checkbox">
<input type="checkbox">
Text </label>
<label class="checkbox">
<input type="checkbox">
Text </label>
</li>
<li class="dropdown-submenu">
<a tabindex="-1" href="#">Centralities</a>
<ul class="dropdown-menu">
<label class="radio">
<input type="radio" name="options" id="optionsRadios1" value="A" checked>
AA </label>
<label class="radio">
<input type="radio" name="options" id="optionsRadios2" value="B">
BB </label><label class="radio">
<input type="radio" name="options" id="optionsRadios2" value="C">
CC </label><label class="radio">
<input type="radio" name="options" id="optionsRadios2" value="D">
DD </label><label class="radio">
<input type="radio" name="options" id="optionsRadios2" value="E">
EE </label>
</ul>
</li>
</ul>
</div>

Answer 1

The best solution:
<div class="dropup">
<ul class="dropdown-menu"></ul>
</div>
It's a native class in bootstrap. The bootstrap (using 3.1.1) css file has a .dropup .dropdown-menu selector so that's how I found out.

Answer 2

It sounds like the answer below would be how to do it from scratch, I was unaware there was a dropup class in Bootstrap...
So the short Bootstrap answer is to apply the class "dropup" to the <ul> in earlier versions of bootstrap:
<ul class="dropdown-menu dropup" role="menu" aria-labelledby="dLabel">
However in newer versions of bootstrap (v3) the "dropup" class needs to be applied to the <ul>'s container instead of the the <ul> itself:
<div class="dropup">
<ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
</div>
See http://jsfiddle.net/ZgyZP/5/
Original working answer that doesn't use bootstrap:
You could use javascript to calculate the height of the submenu and then negatively offset the submenu's position.
something like (with jQuery):
$('.dropdown-submenu').hover(
function(){
//hover in
$('.dropdown-submenu > ul').css('top', '-' + $('.dropdown-submenu > ul').css('height'));
},
//hover out
function(){
}
);
Fiddle: http://jsfiddle.net/ZgyZP/4/

Answer 3

Use a class, like up
<ul class="dropdown up">
Write style of up
.up { bottom:100% !important; top:auto !important; }
Note: Increase bottom as per your button size.

Answer 4

<div class="dropup">
<ul class="dropdown-menu"></ul>
</div>
The above code is correct, but doesn't work unless a parent element has the position property set.
Examples that works are class="col-lg-12" or just
<div style="position: relative;">
I use Bootstrap v3.0.0.

Answer 5

I used the dropup Class, and it worked perfectly as i expected it.
<div class="col-md-6 dropup">
<span uib-dropdown auto-close="outsideClick">
<p class="input-group">
<input type="text" class="form-control" ng-model="int.schTimeFormatted" ng-disabled="true" name="schTime" />
<span class="input-group-btn">
<button type="button" class="btn btn-default cal" uib-dropdown-toggle>
<i class="glyphicon glyphicon-time"></i>
</button>
</span>
</p>
<ul class="dropdown-menu" uib-dropdown-menu aria-labelledby="simple-dropdown">
<li class="timerDropdown">
<div class="row">
<div class="col-md-6">
<div uib-timepicker ng-model="int.schTime" ng-change="changed()" hour-step="hstep" minute-step="mstep" readonly-input="true" min="min"
max="max" show-meridian="ismeridian"></div>
</div>
<div>
Booked Timeslots
<ul id="timeListB">
<li ng-repeat="time in bookedTimeslots">{{time | date:"h:mma"}}</li>
</ul>
</div>
</div>
<hr>
<button class="pull-right">close</button>
</li>
</ul>
</span>
</div>