Character reference
This is a method of notating characters and symbols that cannot be directly described in documents such as HTML and XML using a combination of specific symbols and alphanumeric characters.
There are two types of character references in HTML: numeric character references and character entity references, depending on the notation method.
Here we convert the character entity references in the input string to their original symbols.
Conversely, if you want to convert a character defined as a character entity reference in a string, you can convert it with Convert the character into the character entity reference.
Character entity reference
A character entity reference is a way of specifying a character by a particular predefined string.
For example, the character < is represented by <. This "lt" is an abbreviation for "less than."
Thus, character entity references are more intuitive than numeric character references.
However, special characters that are not defined cannot be converted to character entity references, so only numeric character references are used.