I would like to ask, how you link to the current page? I saw
href="#" method, I saw someone using
href="./" and at another site, an item which represents current page does not have
href. Which method will be the best for SEO?
It depends on what you are expecting. If you want to scroll to a specific part of the page you need to use # as anchor text. This method is fast cause you don't refresh the site, just move inside it.
If you just want to refresh the page, just link to the absolute URL (example.com) or the relative one (/).
As has already been mentioned in comments, linking back to the current page has nothing to do with SEO.
The only reason you might want to do this is as a benefit for your users. To link back to the canonical URL (which might be different to the URL the user is currently on). eg. Stack Exchange does this by linking the question title to the canonical URL. This is just to help users easily grab the canonical URL. The canonical URL is already included in the
<link rel="canonical" element for the benefit of bots.
This results in the page scrolling back to the top. The page is not reloaded.
I saw someone using
This doesn't necessarily link back to the current page. It links back to the current "directory". eg. If you were at the URL
href="./" would link to
an item which represents current page does not have
To link back to the current page then you should use the full absolute URL (with scheme + hostname) or root-relative URL (starting with a slash) - just as if you were linking to any other URL.