How do you Find Object through tags in javascript?

in C sharp you can use this "FindGameObjectWithTag("Player")"

What is the JavaScript equivalent of this?

All Unity functions are available in Javascript. They are the same, so there's no "equivalent".

http://unity3d.com/support/documentation/ScriptReference/index.Accessing_Other_Game_Objects.html

(hit.gameObject.tag == "Naruto")

this will look for the player with the tag naruto :)