Common JavaScript Questions and Answers

1. What is JavaScript?

JavaScript is a scripting language that can be embedded in HTML pages to increase page interactivity and dynamic effects.

2. What is the difference between JavaScript and Java?

Java is a completely different programming language that needs to be compiled into bytecode before it can be run on a virtual machine. JavaScript is a scripting language that can be interpreted and executed directly in the browser.

3. How to declare a JavaScript variable?

Variables can be declared using the var, let, or const keywords.

4. What is DOM?

DOM (Document Object Model) is a way to represent HTML documents as a tree structure, and JavaScript can manipulate HTML elements and attributes through DOM.

5. What is an event?

Events refer to some operations performed by the user on the page, such as mouse clicks, keyboard strokes, and so on. These events can be handled in JavaScript by adding event listeners.

6. How to create functions?

Functions can be created using the function keyword, for example:

function myFunction() {
  console.log("Hello World!");
}

7. How to add elements to HTML pages?

New HTML elements can be created and added using DOM manipulation, for example:

var newElement = document.createElement("p");
var newText = document.createTextNode("This is a new paragraph.");
newElement.appendChild(newText);
document.body.appendChild(newElement);

These are some common JavaScript questions and answers, hope it helps!