Why is the # convention used in empty anchor tag hrefs?

Question

I understand that it's a good idea not to leave empty anchor tags. In jQuery and other syntaxes I've noticed everyone typically uses a # to fill the gap (<a href='#'>anchor text</a>). Is this character any better or worse than filling it with anything else? (e.g. <a href='$'>anchor text</a>). I have no reason to want to do this, but seemingly no reason aside from convention to do it the other way either. Why is the # convention used in empty anchor tag hrefs?

Answer 1

This is because the # character in a URL references the local page.

It is used for named anchors (or any ID) within a page, so a link can jump directly to that area.

Wikipedia calls it the fragment identifier and has this to say:

The fragment identifier, if present, specifies a part or a position within the overall resource or document. When used with HTTP, it usually specifies a section or location within the page, and the browser may scroll to display that part of the page.

---

As a practical example - this link to wikipedia has a fragment identifier (always at the end of the URL):

http://en.wikipedia.org/wiki/Uniform_Resource_Locator#Syntax

In the page, there is a <span id="Syntax" ... tag, and the browser jumps directly to it.