js tutorial

js tutorial

1. declare variable: const, var, let

   • const does not meaning constant

2. operators

   • + string  eg: 'hello'+3 =hello3 2+3+'3' =53
   • comparison operator
     • == equal === equal value and type != not equal !== not equal value and type
   • arithmetic operator
     • +  -  *  /   ** % ++ --
   • Assignment Operators
     • = += -= /= %= **=

3. DATA TYPES

   • Number
   • String
   • Boolean
   • Object { }
   • Array [ ]
   • undefined