what is [class] function in unity-javascript?

Scripting
1

This is part of opensource code…

class AbilityList
{
  var combat;
  
  // Arcane
  var cannonAbility : Ability_ArcaneCannon = new Ability_ArcaneCannon();
  var firecrackerAbility : Ability_Firecracker = new Ability_Firecracker();
  var kineticBlastAbility : Ability_KineticBlast = new Ability_KineticBlast();
  var knitWoundsAbility : Ability_KnitWounds = new Ability_KnitWounds();
  var arcaneArmorAbility : Ability_ArcaneArmor = new Ability_ArcaneArmor();
  var levitateAbility : Ability_Levitate = new Ability_Levitate();
  
  
  // Transmutation
	var swordAbility : Ability_Sword = new Ability_Sword();
	var boomerangAbility : Ability_Boomerang = new Ability_Boomerang();
	var spikeAbility : Ability_Spike = new Ability_Spike();
	var whipAbility : Ability_Whip = new Ability_Whip();
	var siphonSpeedAbility : Ability_SiphonSpeed = new Ability_SiphonSpeed();
	var seraphicWingsAbility : Ability_SeraphicWings = new Ability_SeraphicWings();
}

What that [class] does and how it works that come out firstly?

What is difference from normal var and var in child of class?

2

class means you´re creating a class. If you don´t write this on the first line of your code, Mono considers your class the name of the file and insert that line when the code is compiled for you. There´s no difference between variables in both situations.