Question

Anything I tried failed so far to get Firefox to underline some text.

According to Google-results this issue is known and documented for more than five years … that just can’t be true … what is going on?

Someone knows any consitently working workaround or maybe even a reason as to why they didn’t fix it yet!? … I am very curious about that

Answer 1

In my Firefox, a ForeignObject text within an SVG gets perfectly underlined if I include it in the right tags:

<html:u>blub</html:u>

… having declared html as a namespace in the svg, sample code looks like this:

<div style="border:solid black 2px;">
<svg:svg xmlns="http://www.w3.org/2000/svg"
  xmlns:html="http://www.w3.org/1999/xhtml"
  width="300" height="50" > 
 <foreignObject width="80" height="50">
   <html:u>blub</html:u>
 </foreignObject>
</svg:svg>
</div>

Would that be a solution for you?