How to prevent domain prefix when loading/fetching CKEditor href?

I’m trying to implement an <a href=tel:{string}>{string}</a> functionality in Typo3, using CKEditor and Typo3:s built in Linkbrowser.

I have found a Github project, https://github.com/visuellverstehen/t3telephone, that works insofar there’s a new tab included in the Linkbrowser and when entering a number, the link is inserted in CKEditor in the format described above.

Now, where I’m getting stuck is that when I load the content element (it’s Typo3:s built in Text element), the domain name of the site the content element belongs to is prefixing the href attribute, but only if the value entered is an integer…? Example;

  • Entering the string +1234 results in: <a href="tel:+1234">{string}</a>
  • Entering the string 1234 results in: <a href="https://the.domain.here/tel:+1234">{string}</a>

Saving the data seem alright. In both cases the information in bodytext of the content element is as it was wnitten, ...tel:+1234... and ...tel:1234... respectively. Something seem to happen when fetching the data again.

This issue is not showing up on links such as the Typo3 built-in email type. It only affects custom made/registered link types.

I’ve been fighting this for some time now. Does anyone have an idea as to why it behaves like this?

This is pre Typo3 10, so we don’t have the luxury of using the core included telephone functionality.

This issue is not showing up on links such as the Typo3 built-in email type. It only affects custom made/registered link types.

I just tested this more thoroughly. Even mailto:-links are affected by this; If you only type an integer, the domain will prefix the link. This is of course a non-issue with email-links, because they will contain at least an @-character, but I still don’t understand why for integers the domain is prefixing the value when loading a content-element containing a link with only integers.