Originally Posted by jihanemo
And another question, when referencing web pages in your relative or absolute paths, is it necessary to place ".html" at the end?
Such as "../help.html" ... ?
Yes, you need to put the extension because you can have a help.html and a help.php file with different contents (not that this is good practice but theoretically it’s possible) and how would the browser know what file to look for.
However, there are methods to circumvent this “restriction”. Search for “pretty URLs” or “htaccess URL rewriting” or something like that.