Are there any browser issues with <a> tags that lack an href attribute?
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Context: Currently, Wt (Web Toolkit) will render a WAnchor object as a `<span>` tag rather than an `<a>` tag if the link that the anchor should point to, is empty.

However, there are some problems with this approach, notably that it adds unnecessary complexity to CSS styling (when using Twitter Bootstrap, for example).

I've been involved in a discussion with one of the Wt developers proposing a patch to change this behavior: http://redmine.emweb.be/issues/1348

He noted that the current behavior was implemented as a result of certain browsers having problems rendering `<a>` tags without an `href` attribute (possibly older mobile browsers?).

According to the official HTML specifications, there is no problem with this:

* http://dev.w3.org/html5/spec/single-page.html#the-a-element *If the a element has no href attribute, then the element represents a placeholder for where a link might otherwise have been placed, if it had been relevant.*
* http://www.w3.org/TR/html401/struct/links.html#edef-A *Authors may also create an A element that specifies no anchors, i.e., that doesn't specify href, name, or id. Values for these attributes may be set at a later time through scripts.*

And as far as I am aware...

    <a>Link</a> // OK
    <a href>Link</a> or <a href="">Link</a> // Undefined? (but common behavior is to navigate to the current URL)
    <a href="/items">Link</a> // OK

I also checked the following document with the W3C HTML5 validator:

    <!DOCTYPE html>
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Untitled Document</title>
    </head>
    <body>
    <a>Example of an anchor with no href attribute.</a>
    <a href>Example of an anchor with a null href attribute.</a>
    <a href="">Example of an anchor with an empty string href attribute.</a>
    <a href="http://www.google.com/">Example of an anchor that links to Google.</a>
    </body>
    </html>

I received one warning:

> `Line 9, Column 8: Attribute href without an explicit value seen. The
> attribute may be dropped by IE7. <a href>Example of an anchor with a
> null href attribute.</a>`

So my question is: are there any known situations where the **total** lack of an `href` attribute on an `<a>` tag causes problems in certain browsers? IE? Mobile Safari?