regex 2 characters or more code example

Example 1: Regular Expressions: Match Single Character with Multiple Possibilities

let quoteSample = "Beware of bugs in the above code; I have only proved it correct, not tried it.";
let vowelRegex = /[aeiou]/gi; // Change this line
let result = quoteSample.match(vowelRegex); // Change this line

Example 2: regex match two characters

echo %H#E%L#L%O! | sed 's/[#%]//g'	#replaces every appearance of any of
two characters # and %