Most likely, as mentioned by others, it is a class carrying the css values:
.clear{clear: both;} in order to prevent any more page elements from extending into the footer element. It is a quick and easy way of making sure that pages with columns of varying heights don't cause the footer to render oddly, by possibly setting its top position at the end of a shorter column.
In many cases it is not necessary, but if you are using best-practice standards it is a good idea to use, if you are floating page elements left and right. It functions with page elements similar to the way a horizontal rule works with text, to ensure proper and complete sepperation.
A class in HTML means that in order to set attributes to it in CSS, you simply need to add a period in front of it.
For example, the CSS code of that html code may be:
.clear { height: 50px; width: 25px; } Also, if you, as suggested by abiessu, are attempting to add the CSS clear: both; attribute to the div to prevent anything from floating to the left or right of this div, you can use this CSS code:
.clear { clear: both; } Source: Stackoverflow.com