=== will check for equality of two values. If two values are not of the same type, === will return false.
== on the other hand will attempt to convert types to match and check the equality.
The same goes for != and != =, which perform the same thing, but negated.
Below are a few examples where these equality operators can be seen in use:
false == ‘0’ //true
false === ‘0’ //false
null == undefined //true
null=== undefined //false
Unless type conversion is explicitly desired, it’s typically best to use === and == over == and !=, to avoid any unintended side-effects of type conversions.