How Can I Check if a JavaScript Variable is Undefined or Null?

Determining the Undefined or Null Status of a Variable

In your provided code, the JavaScript interpreter halts execution because you are comparing a string with an undefined value. To determine if a variable is undefined or null, you should utilize the abstract equality operator (==) rather than the strict equality operator (===).

The abstract equality operator evaluates both values as loose specifications, allowing for type conversions. In this case, if the variable EmpName is undefined or null, the comparison EmpName == 'undefined' would evaluate to true. Here's the revised code:

var EmpName = $("#esd-names div#name").attr('class');
if (EmpName == null) {
  // Execute your logic
}

This code will accurately handle both scenarios where EmpName is either undefined or null, allowing you to proceed with your intended actions.

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