save bookmark with relative path to current-site
javascript:void(window.location.href = '/path-to-some-page');
Is another way of bookmarking a relative path.
I haven't seen a way to save a relative or root-relative link without resorting to a bookmarklet.
As far as a bookmarklet is concerned, it's relatively easy to generate one that will take you to whatever path you'd like:
javascript:(rel=>{location=rel.startsWith('/')?`${location.protocol}//${location.host}${rel}`:`${location.protocol}//${location.host}${location.pathname}/${rel}`})('/path')
Replace 'path'
at the end with a properly escaped string containing whatever path you'd like. Note that this will differentiate between relative and root-relative paths based on whether they start with a /
character.
In long form:
(rel => { location = // if the relative path starts with / rel.startsWith('/') // go to http(s)://{domain}/{relative path} ? `${location.protocol}//${location.host}${rel}` // otherwise go to http(s)://{domain}/{current path}/{relative path} : `${location.protocol}//${location.host}${location.pathname}/${rel}`// call the function providing the relative path to use})('/path')