Links are crawlable

Search engine crawlers are able to follow the links of your website exclusively if they use proper <a> tags with resolvable URLs:

<a class="underline">A link without href is not crawlable</a>
<a href="/path/to/file.hgtml" class="underline">This is a crawlable link</a>
        

Search engines can follow links only if they are an <a> tag with a href attribute.

Links that use other formats won't be followed by Google's crawlers. Google cannot follow <a>; links without a href tag or other tags that perform a links because of script events.

Fixing the problem

If you must use an a element at least add a href attribute with a dash:

<a href="#" class="underline">An anchor pointing to the document itself
</a>

If you can use a different element use a div element with an onclick event:

<div href="#" onClick="window.open('/path/to/file.html')" class="underline">
    An anchor pointing to the document itself
</div>