Priority Queue Code Problems

So Javascript doesn't support priority queues?

That code is Javascript; Unity doesn't use that, it uses Unityscript (confusingly called Javascript, it's true). You'd have much better luck finding ActionScript 3 code or C# code and translating that to Unityscript.

Oh... that makes sense. So I'm just out of luck then?

No...as I said, find some other code and adapt it to Unityscript. You could adapt that Javascript code, for that matter, but it would be easier to adapt C# code. Or you can write your own; see Bunny83's answer.

Although, if you mean "is there any pre-existing Unityscript code for priority queues that I can copy and paste", then probably yes you are out of luck, or at least I don't know of any. (If you can use a plain old queue, rather than a priority queue, that's built in to .Net/Mono so you can just use that.)

Well, I'm developing an A* pathfinding system and it works I'm just trying to optimize it as much as possible (without using C#). Are my other options better? If I have to use C# then can I write the AI code in C# but use it on my character who is coded in Unityscript?