How to Properly Check for Undefined or Null Variables in JavaScript?

How to Distinguish 'Undefined' and 'Null' Variables

In your code, you attempt to check if the EmpName variable is undefined by comparing it to the string 'undefined'. However, this approach triggers an error due to a type mismatch. To accurately determine if a variable is undefined or null, employ the JavaScript abstract equality operator (= =):

if (variable == null) {
    // your code here.
}

This code snippet exploits the fact that abstract equality checks for values that are functionally identical, including null and undefined. Thus, it successfully captures both cases in your scenario.

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