JavaScript Quiz #3

Understanding JavaScript by example is useful for absorbing the different concepts of the language quickly. In this post, I will illustrate a quick JavaScript Quiz to understand how JavaScript (+) operator works. Assume that we have the following JavaScript code:

var object1 = {
    someVar: 2,
    someName: "object1",
    valueOf: function () {	
        return this.someVar;
    toString: function () {	
        return this.someName;

var result = "I equal " + object1;

alert(result); //What is the output of the alert?

What is the output of the alert?

Read the complete answer

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About Hazem Saleh

Hazem Saleh has more than eleven years of experience in Cloud, Mobile and Open Source technologies. He worked as a software engineer, technical leader, application architect, and technical consultant for many clients around the world. He is an Apache PMC (Project Management Committee) member and a person who spent many years of his life writing open source software. Beside being the author of the "JavaScript Unit Testing" book, "JavaScript Mobile Application Development" book, "Pro JSF and HTML5" book and the co-author of the "Definitive guide to Apache MyFaces" book, Hazem is also an author of many technical articles, a developerWorks contributing author and a technical speaker in both local and international conferences such as ApacheCon North America, Geecon, JavaLand, JSFDays, CON-FESS Vienna and JavaOne. Hazem is an XIBMer, he worked in IBM for ten years. Now, He is working for Nickelodeon New York as a Mobile Architect. He is also an OpenGroup Master Certified Specialist.