Javascript Variables

Writing by on Thursday, 25 of October , 2007 at 4:46 pm

Remember, Javascript is not a strongly typed language. While using variables in Javascript, don’t bother about the type of data a variable is storing, instead what the variable is storing. These variables can store anything – even functions!! Here are some examples on using variables in Javascript.

var thisIsAString = 'This is a string';
var alsoAString = '25';
var isANumber = 25;
var isEqual = (alsoAString==isANumber);  // This is true, they are both 25.
var isEqual = (alsoAString===isANumber); // False one is a number,
                                         // the other a string.

var concat=alsoAString + isANumber;      // concat is now 2525
var addition=isANumber + isANumber;      // addition is now 50
var alsoANumber=3.05;     // is equal to 3.05 (usually).
var floatError=0.06+0.01; // is equal to 0.06999999999999999
var anExponent=1.23e+3;   // is equal to 1230

var hexadecimal = 0xff;   // is equal to 255.
var octal = 0377;         // is equal to 255.

var isTrue = true;   // This is a boolean, it can be true or false.
var isFalse= false;  // This is a boolean, it can be true or false

var isArray = [0, 'one', 2, 3, '4', 5]; // This is an array.
var four = isArray[4]; // assign a single array element to a variable.
                       // in this case four = '4'

var isObject = { 'color': 'blue',  // This is a Javascript object
                 'dog': 'bark',
                 'array': [0,1,2,3,4,5],
                 'myfunc': function () { alert('do something!'); }

var dog =;  // dog now stores the string 'bark';
isObject.myfunc();       // creates an alert box with the value "do something!"
var someFunction = function() {
                      return "I am a function!";
var alsoAFunction = someFunction; //No () so alsoAFunction becomes a function
var result = alsoAFunction(); // alsoAFunction is executed here because ()
                              // executes the function so result stores the
                              // return value of the function which is
                              // "I am a function!"

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Category: Javascript

Shivdev Kalambi's Blog

Shivdev Kalambi is a Software Development Manager, previously a Principal Software Engineer at ArcSight/HP. With over 16 years' experience in software development, he's worked on several technologies and played different roles and contributed to all phases of projects. Non-tech activies include Ping-pong, Rock Climbing and Yoga at PG, Golf, Skiing, Swimming & a beer enthusiast.