In order to find and remove any silent error in a JavaScript code, “use strict”; expression is used. This expression is placed as the first statement in the code to enable the strict mode of debugging. Note: It will throw an error if there is there any silent error in the JavaScript code. Example: <!DOCTYPE … Read more
The mechanism of using variables and functions before their declarations by moving their declarations to the top of the code is called hoisting in Javascript. Example: <!DOCTYPE html> <html> <head> </head> <body> <script> document.write(mul(2,5,6)); function mul(a,b,c) { return a*b*c; } </script> </body> </html>
Debugging can be simply defined as a process of finding errors in a code before actual execution. A JavaScript code can be debugged using a built-in web browser debugger, in the following two ways: Using console.log() method Using debugger keyword Using console.log() method It is used to generate an error message on the console of … Read more
this keyword in JavaScript is used to refer to a specific object. Now the point comes to which object this keyword will refer to. We can have below 4 scenarios for calling this keyword. Global Scope Object’s Method call() or apply() method bind() method this – Global Scope: this keyword will point to the window … Read more
When an HTML event occurs, HTML DOM allows JavaScript to respond accordingly. Some of these HTML events are: Onclick Occurrence: when an element is clicked. Ondblclick Occurrence: when an element is double-clicked. Onfocus Occurrence: when an element gets focus such as button, input, textarea, etc. Onblur Occurrence: when form loses the focus from an element. … Read more
Javascript facilitates multiple ways of deleting cookies. These are as follows: 1. Delete the cookie by using the expire attribute document.cookie = ‘name=Mahesh; expires=Sun, 19 May 2019 18:04:55 UTC’ 2. Delete the cookie by using the max-age attribute document.cookie = ‘name=Vishal; max-age=7200’ 3. Delete cookie explicitly by using a web browser Example: <!DOCTYPE html> <html> … Read more
In order to store multiple name-value pairs of cookies in javascript, the custom object must be serialized in a JSON string which is then parsed and stored in a cookie. A separate cookie can also be used for each name-value pair. Example: <!DOCTYPE html> <html> <head> </head> <body> Username: <input type=”text” id=”name”><br> Mail_ID: <input type=”email” … Read more
To enhance the functionality of cookies, some optional attributes may be used in Javascript. expires: Used to maintain the state of a cookie up to the specified date and time. document.cookie = ‘name=Jai; expires=Sun, 19 May 2019 18:04:55 UTC’ max-age: Used to maintain the state of a cookie up to the specified time in seconds. … Read more
As HTTP is a stateless protocol i.e. all requests to the server are treated as new requests and there is no way to determine if a request comes from a user who already did a request before or if it is a new user. A cookie is a small piece of information that the server … Read more
Abstraction is a way of hiding complexity. The JavaScript Data Abstraction feature is used for hiding internal details and showing the essential features of the object only. Note: We can not instantiate the Abstract class. Example: <!DOCTYPE html> <html> <body> <script> function Student() { this.Name=”Name”; throw new Error(“You cannot create an instance of Abstract Class”); … Read more