This is a list of tags and their functions when written and interpreted, which I've been looking for a long time, Its simple and has a simple description of what they do:
http://www.w3schools.com/tags/default.asp
(this Is optional to read)
click on them for more advanced info and ideas on how to use the tag
there is also a picture/example that is interactable(clicking "try it yourself") to see how it works which will make you ask questions and which they were nice to have the answers below the example
On the left side margin, you can select how the tags are listed under "HTML Reference" by Function:
(which is listed from Basic to advanced, nice for beginners like me)or by Alphabet (to scroll through faster)
Maybe there is a better place for tag reference but I like w3schools since its very simple and quick to learn.I try learning this only to fullfill my vision of a first-time ever survival-horror browser game , not to hack or disrupt someones computer like those antivirus companies are doing for profit
If you think there's better places or there's something wrong or alternatives, post it, this is also the place where I learned a litttle bit of HTML, not PHP.net/.com/.whatever. I strongly recommend to learn PHP from here, I tried others, trust me.
"Tags" is reserved for mark-up languages such as HTML, XHTML, XAML or XML.