What is the use of for-in loop in JavaScript? Unshift() method is an array method used for inserting an element at the beginning of an array. Push() method is an array method used for inserting an element at the end of an array.įor example, const arr = What is the difference between push & unshift methods of an array in JavaScript? What are the methods for accessing & manipulating the document object model (DOM)?ġ5. It is a hierarchical representation of an HTML document. What is DOM in JavaScript?ĭOM stands for Document Object Model.

Typeof operator is used for checking the data type of a variable or value. What is the usage of typeof operator in JavaScript? It can be assigned to a variable to indicate that it currently has no value but will do so in the future. Null in JavaScript represents the absence of any value. In JavaScript, undefined signifies that a variable has been declared but not assigned a value or that it has not been declared at all. Mention the different types of pop-up boxes in JavaScript.Ĭonst value = confirm(“Do you want to continue?”) What would be the output of the JavaScript code given below? console.log(5+3+'6') The style of a HTML element can be changed in 2 ways:ĮtAttriute(‘style’, cssProperty) įor example, tAttribute('style', 'background-color: yellow ') įor example, ='yellow' Ĩ. How can the style of an HTML element be changed using JavaScript? It refers to the owner object in a method and the global object in a function.

Depending on where it is used, the “this” has multiple values. ‘this’ keyword in JavaScript refers to the object from where it was called. In JavaScript, what do you mean by “this” keyword? It returns true if the given value is not a number, otherwise false. What is the usage of isNaN in JavaScript? Yes, because the data type of variables is decided at runtime, JavaScript is a dynamically typed language. Is JavaScript a dynamically typed language? ‘=’ returns true if two values are same whereas ‘=’ returns true if the data type & value of a variable are the same.

Javascript interview questions