How to make <div> fill <td> height

I've looked through several posts on StackOverflow, but haven't been able to find an answer to this rather simple question.

I have an HTML construct like this:

<table>
  <tr>
    <td class="thatSetsABackground">
      <div class="thatSetsABackgroundWithAnIcon">
        <dl>
          <dt>yada
          </dt>
          <dd>yada
          </dd>
        </dl>
      <div>
    </td>
    <td class="thatSetsABackground">
      <div class="thatSetsABackgroundWithAnIcon">
        <dl>
          <dt>yada
          </dt>
          <dd>yada
          </dd>
        </dl>
      <div>
    </td>
  </tr>
</table>

What I need is for the div to fill the height of the td, so I can be able to position the div's background (the icon) at the bottom-right corner of the td.

How do you suggest I go about that?

If you give your TD a height of 1px, then the child div would have a heighted parent to calculate it's % from. Because your contents would be larger then 1px, the td would automatically grow, as would the div. Kinda a garbage hack, but I bet it would work.

CSS height: 100% only works if the element's parent has an explicitly defined height. For example, this would work as expected:

td {
    height: 200px;
}

td div {
    /* div will now take up full 200px of parent's height */
    height: 100%;
}

Since it seems like your <td> is going to be variable height, what if you added the bottom right icon with an absolutely positioned image like so:

.thatSetsABackgroundWithAnIcon {
    /* Makes the <div> a coordinate map for the icon */
    position: relative;

    /* Takes the full height of its parent <td>.  For this to work, the <td>
       must have an explicit height set. */
    height: 100%;
}

.thatSetsABackgroundWithAnIcon .theIcon {        
    position: absolute;
    bottom: 0;
    right: 0;
}

With the table cell markup like so:

<td class="thatSetsABackground">  
  <div class="thatSetsABackgroundWithAnIcon">    
    <dl>
      <dt>yada
      </dt>
      <dd>yada
      </dd>
    </dl>
    <img class="theIcon" src="foo-icon.png" alt="foo!"/>
  </div>
</td>

Edit: using jQuery to set div's height

If you keep the <div> as a child of the <td>, this snippet of jQuery will properly set its height:

// Loop through all the div.thatSetsABackgroundWithAnIcon on your page
$('div.thatSetsABackgroundWithAnIcon').each(function(){
    var $div = $(this);

    // Set the div's height to its parent td's height
    $div.height($div.closest('td').height());
});
  

You could try making your div float:

.thatSetsABackgroundWithAnIcon{

    float:left;
}

Alternativelly, use inline-block:

.thatSetsABackgroundWithAnIcon{

    display:inline-block;
}

Working example of the inline-block method:

table,
th,
td {
  border: 1px solid black;
}

<table>
  <tr>
    <td>
      <div style="border:1px solid red; height:100%; display:inline-block;">
        I want cell to be the full height
      </div>
    </td>
    <td>
      This cell
      <br/>is higher
      <br/>than the
      <br/>first one
    </td>
  </tr>
</table>

Really have to do this with JS. Here's a solution. I didn't use your class names, but I called the div within the td class name of "full-height" :-) Used jQuery, obviously. Note this was called from jQuery(document).ready(function(){ setFullHeights();}); Also note if you have images, you are going to have to iterate through them first with something like:

function loadedFullHeights(){
var imgCount = jQuery(".full-height").find("img").length;
if(imgCount===0){
	return setFullHeights();
}
var loaded = 0;
jQuery(".full-height").find("img").load(function(){
	loaded++;
	if(loaded ===imgCount){
		setFullHeights()
	}
});

}

And you would want to call the loadedFullHeights() from docReady instead. This is actually what I ended up using just in case. Got to think ahead you know!

function setFullHeights(){
var par;
var height;
var $ = jQuery;
var heights=[];
var i = 0;
$(".full-height").each(function(){
	par =$(this).parent();
	height = $(par).height();
	var tPad = Number($(par).css('padding-top').replace('px',''));
	var bPad = Number($(par).css('padding-bottom').replace('px',''));
	height -= tPad+bPad;
	heights[i]=height;
	i++;
});
for(ii in heights){
	$(".full-height").eq(ii).css('height', heights[ii]+'px');
}

}

This questions is already answered here. Just put height: 100% in both the div and the container td.

Modify the background image of the <td> itself.

Or apply some css to the div:

.thatSetsABackgroundWithAnIcon{
    height:100%;
}