Dynamic Height Code

Here is a css code called clearfix:

.clearfix:after {
 content: ".";
 display: block;
 height: 0px;
 clear: both;
 visibility: hidden;
}
.clearfix {display: inline-block;}

/* Hides from IE-mac \*/
* html .clearfix {height: 1%;}
.clearfix {display: block;}
/* End hide from IE-mac */

Use it when items in a container is longer than the outer container or is unpredictable. This css code will make the outer container have a fixed height. Then you could use Element.getDimensions() to get the computed css height of that container.