Let’s say, need a character string like this “64d3ab4de4bae1091e5de441” wiht only digitnumbers, lowercase and Upper case letters from a to f, and A to F respectively and 24 characters.
Regex offers a way to match this type of strings.
In this case, the regex expression would be as follows:
/^[0-9a-fA-F]{24}$//^ this is the start
$/ this is the end
[0-9a-fA-F] this indicates that it should be digitnumbers from 0 to 9, and string characters from a to f, and A to F, respectively.
{24} this, in curly brackets, the number of characters
that is all