Marusya's School Notes

The Typeof Operator

You can use the JavaScript typeof operator to find the type of a JavaScript variable:

typeof "John" <=== string data type
typeof 3.14 <=== number data type
typeof false <=== boolean data type
typeof [1,2,3,4] <=== object data type
typeof {name:'John', age:34} <=== object data type

HTML file:	Displayed by browser:
<body> <p>The typeof operator returns the type of a variable or an expression.</p> <p id="demo"></p> <script> document.getElementById("demo").innerHTML = typeof "john" + "<br />" + typeof 3.14 + "<br />" + typeof false + "<br />" + typeof [1,2,3,4] + "<br />" + typeof {name:'john', age:34}; </script> </body>	The typeof operator returns the type of a variable or an expression.

HTML file:

Displayed by browser:

<body>
<p>The typeof operator returns the type of a variable or an expression.</p>
<p id="demo"></p>
<script>
   document.getElementById("demo").innerHTML =
   typeof "john" + "<br />" +
   typeof 3.14 + "<br />" +
   typeof false + "<br />" +
   typeof [1,2,3,4] + "<br />" +
   typeof {name:'john', age:34};
</script>
</body>

The typeof operator returns the type of a variable or an expression.

In JavaScript, an array is a special type of object. Therefore typeof [1,2,3,4] returns object.