Use typeof operator to check if a variable is a primitive type or undefined or object in JavaScript

Description

The following code shows how to use typeof operator to check if a variable is a primitive type or undefined or object.

Example


<!-- w ww.  j a v a2  s. co m-->

<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
var s = "JavaScript";
var b = true;
var i = 22;
var u;
var n = null;
var o = new Object();
document.writeln(typeof s); //string
document.writeln(typeof b); //boolean
document.writeln(typeof i); //number
document.writeln(typeof u); //undefined
document.writeln(typeof n); //object
document.writeln(typeof o); //object
</script>
</head>
<body>
</body>
</html>

Click to view the demo

The code above generates the following result.

Use typeof operator to check if a variable is a primitive type or undefined or object in JavaScript

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Use typeof operator to check if a variable is a primitive type or undefined or object in JavaScript

Description

Example

Use typeof operator to check if a variable ...