Scripting questions

[iDigzy]

Hi, I recently started scripting GS2 and I have a few questions.
1. What are classes for, like difference between weapons?
2. What is the point of npc's option when you can add npc's in level editor? Is it the same?
3. For setting things for a player, for example the hat or head would the script be something like player.attr1 = "filename"?
4. Are there any "and" or "or" words that can be used in an if statement? For example, a script like
function onPlayerchats() {
if (player.chat = "hello") *could you put an "and" or an "or" comparison here?* {
player.chat = "hi"
}