Why do people write HTML like this? [closed]

Question

I've noticed a lot of people who don't use quotation marks when they write HTML. For example:

<li class=somename>blabla</li>
instead of
<li class="somename">dkdk</li>

Where are they getting this from?

Answer 1

From the HTML 4.01 specification:

In certain cases, authors may specify the value of an attribute without any quotation marks. The attribute value may only contain letters (a-z and A-Z), digits (0-9), hyphens (ASCII decimal 45), periods (ASCII decimal 46), underscores (ASCII decimal 95), and colons (ASCII decimal 58). We recommend using quotation marks even when it is possible to eliminate them.

But in XHTML quotation marks are required to be well-formed XML (see also XHTML 1.0: Differences with HTML 4 – Attribute values must always be quoted).