, Pound sign: indicates a position in a webpage, called an anchor, and is often used to jump to a different position between a webpage. Simply put, in a webpage, the URL is unchanged, by adding "# The character of "buy" can jump to the anchor point (id = "buy") that has been defined in the current web page at the end of the URL
?, Question mark: commonly used in dynamic websites, to achieve different parameter values and generate different pages or return different results, for example, the dynamic link of WordPress is /? P = ID, where p means post article, ID means article ID, so you can access different articles by article ID.
&, Connector: Since it is called a link symbol, that is the role of the connection, and it can also be said to be a spacer for different parameters. It is generally used in conjunction with the question mark. In a dynamic URL link, the first parameter starts with the question mark, which is connected with Operator to concatenate multiple parameters and values.