Computer Science Major required - attack methods (XSS, DOS and DDOS)

separate to 2 parts, i knew the definition. what i need is how they work. This paper is not a homework assisgnment.

doesnt need prefect writting, just helping me to understand what are those methods. but please give your references.

at least 250 words for each part.

part1 : explain what is XSS, how it works, give examples, how attackers use this method to steal information.

part2: talking about the differences of DOS and DDOS, how it works, give examples, explain the attack process. how attackers shut down the server/website by using these methods.