How can I determine if a variable is 'undefined' or 'null'?

javascript, jquery, null, undefined, variables

Solution

You can use the qualities of the abstract equality operator to do this:

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

Because `null == undefined` is true, the above code will catch both `null` and `undefined`.

Problem

How do I determine if a variable is `undefined` or `null`? My code is as follows: ``` var EmpName = $("div#esd-names div#name").attr('class'); if(EmpName == 'undefined'){ // DO SOMETHING }; ``` ``` <div id="esd-names"> <div id="name"></div> </div> ``` But when I do this, the JavaScript interpreter halts execution.

Original source

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