IDs and classes are both pretty common attributes, so Jade gives us a shorthand method for writing them. This is similar to the way CSS selectors are written. An example of this is as follows:

p#hello Hello Word!

<p id="hello">Hello Word!</p>

p#hello.world

<p id="hello" class="world"></p>

Pretty familiar, eh? IDs are just prefixed with a # (pound symbol) and classes are prefixed with . (a period). These may be put in any order after the tag name with any number of classes.

Because the div tags are used so frequently, Jade offers a shorthand way for writing them; by omitting the tag, Jade assumes you want to use a div tag; therefore, the following code:

div#hello Hello Word!

<div id="hello">
Hello Word!
</div>

It can also be rewritten as:

#hello Hello Word!

<div id="hello">
Hello Word!
</div>

However, this is possible only as long as there is an ID and/or class where the tag name...