Top 35 Essential JavaScript Interview Questions and Answers

• JavaScript is open and cross-platform.
• JavaScript is a lightweight, interpreted programming language.
• JavaScript is client side scripting language.
• JavaScript is easy to integrate with HTML.
• JavaScript is complementary to and integrated with Java.
• JavaScript is designed for creating network-centric applications.

Bubbling :-

Capturing :-

<script>

   $(‘input:textbox’).val();

</script>

<script>

    $("p").removeClass("perag");

</script>

<script>

  var t = “Hello World”;  

  console.log(t);

  </script>

<script>

    $(‘.selected’);

</script>

var str='I Love PhpMyPassion.com';
str = str.toLowerCase();
console.log(str);

window.history.pushState('page2', 'I Love PhpMyPassion', '/nextpage.php');

var today = new Date();
console.log(today);

window.open('http://www.phpmypassion.com/','_blank');

var CONSTANT_NAME = "constant value";

/** Here stClass is parameter in which we have set the default value i.e senior_secondary **/
function functionGetClass(name, stClass)
 {
   stClass = typeof stClass !== 'undefined' ? stClass : 'senior_secondary';
    console.log('name='+name+', Class= '+stClass);
 }

functionGetClass('raj','secondary');
functionGetClass('raj');

var pobject=['Php','Is','My','Passion']
JSON.stringify(pobject);

var jsonpData = '{"name":"phpmypassion","year":2017}';
var pobject = JSON.parse(jsonpData);
console.log(pobject);

if( /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ) {

}

 if(navigator.userAgent.match(/Android/i) || navigator.userAgent.match(/webOS/i) ||  navigator.userAgent.match(/BlackBerry/i) || navigator.userAgent.match(/iPhone/i)){
        console.log('Calling from Mobile');      
    }else{
    console.log('Calling from Web');      
}

var myNamespace = {

    functionA: function() {   },

    functionB: function() {    }

    functionC: function() {    }
};

myNamespace.functionC();

var x = [];
var y = [1, 2, 3, 4, 5];

var student= {
   name: "sonia",
   age: 20
};

// Getting object properties
student.name  // ==> sonia
student.age   // ==> 20
// Setting object properties
student.name = "monica"  // <== monica
student.age  = "22"      //  <== 22

function name(){
   // do some stuff here
}