Question

I was reading the code in the official demo page for slider: http://jqueryui.com/demos/slider/ and I was wondering why an <a> tag is used for handle? Why not a <div>?

<div class="demo">

<div id="slider" class="ui-slider ui-slider-horizontal ui-widget ui-widget-content ui-corner-all">
    <a class="ui-slider-handle ui-state-default ui-corner-all ui-state-hover" href="#" style="left: 19%; ">
    </a>
</div>

</div>

Answer 1

I think they used an anchor because in HTML links are what separate HTML from other markup languages because they provide interaction. Taken from w3c

HTML offers many of the conventional publishing idioms for rich text
and structured documents, but what separates it from most other markup
languages is its features for hypertext and interactive documents.
This section introduces the link (or hyperlink, or Web link), the
basic hypertext construct. A link is a connection from one Web
resource to another. Although a simple concept, the link has been one
of the primary forces driving the success of the Web.

And the handle is also something you click, so maybe they thought that semantically made more sense using an <a> instead of a <span>.

To make it clear, my thought is that they could have used anything technically but they choose an anchor for semantic reasons