classic NS2 string operations
length, charAt(pos), indexOf(substring), lastIndexOf(substr)
slice(from, to) == substring(from, to), substr(from, length)
toLowerCase(), toUpperCase()

silly html generators nobody ever uses:
anchor(), big(), blink(), bold(), fixed(), fontcolor(), fontsize(),
italics(), link(), small(), strike(), sub(), sup()

NS3:
Array words = sentence.split(" ")
since Array.join() was introduced with NS3 i have my doubts that
string.split() was introduced with NS2 as some documentation states..

NS4/IE4 news:
charCodeAt(pos), concat(appendString), fromCharCoWe(),
regular expressions: match(), replace(), search()