Build an hreflang <link rel="alternate"> tag. Validates hreflang against BCP-47 / x-default pattern and requires a branded AbsoluteUrl for the href to prevent injection.
<link rel="alternate">
hreflang
x-default
Language code (or x-default)
Branded absolute URL of the alternate page
Complete <link> tag string
<link>
when hreflang does not match expected pattern
Build an hreflang
<link rel="alternate">tag. Validateshreflangagainst BCP-47 /x-defaultpattern and requires a branded AbsoluteUrl for the href to prevent injection.