What is var

Im trying to debug a few javascripts, and wondering if there is a way of finding out if a var is a string, int, long, float etc?

For example, if I use:-
var x=5;
var carname="Volvo";

Open in new window

Is it possible to detect what x is stored as, or carname?
Who is Participating?
leakim971Connect With a Mentor PluritechnicianCommented:
vars are not typed (you can change their type at any moment),  you may use typeof keyword to know the current type of a var : https://developer.mozilla.org/en/JavaScript/Reference/Operators/typeof

var x=5;
alert( "type of x is " + typeof x);
var carname="Volvo";
alert( "type of x is " + typeof carname);

Open in new window

test page : http://jsfiddle.net/2VLW4/
Dave BaldwinFixer of ProblemsCommented:
"You declare JavaScript variables with the var keyword:"  http://www.w3schools.com/js/js_variables.asp
Noooooo, var is used to define a local variable - see below:

hello = "Hello ";
world = "World!"

function sample() {
    hello = "Goodnight ";
    var world = "Vienna!";

new sample();
alert( hello + world ); // => Goodnight World!

Open in new window

Introducing Cloud Class® training courses

Tech changes fast. You can learn faster. That’s why we’re bringing professional training courses to Experts Exchange. With a subscription, you can access all the Cloud Class® courses to expand your education, prep for certifications, and get top-notch instructions.

Lee SavidgeCommented:
Anuradha GoliSystems Development / Support SpecialistCommented:
var simple refers to variable means it can be changed during the code.
You can get data type of variable using typeof.

  <script type="text/javascript">
        var firstname;
        document.write("<br />");

returns number,
If firstname="12" then it returns string
Lee SavidgeCommented:
The question asker isn't asking what "var" is. The query is with respect to finding out the type which you can use typeof to determine that.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.