100 SQL Coding Questions & Answers

JavaScript Coding Questions & Answers

Beginner Level

Q1. What is JavaScript?

JavaScript is a scripting language used to create dynamic web pages.

Q2. How to include JavaScript in HTML?

<script src="script.js"></script>

Q3. Print message in console.

console.log("Hello");

Q4. Declare a variable.

let x = 10;

Q5. Difference between var, let, const.

var = function scope, let = block scope, const = constant value.

Q21. What is DOM?

DOM represents the HTML document as objects.

Q22. Query selector.

document.querySelector(".box");

Q23. Add event listener.

btn.addEventListener("click", function(){
  alert("Clicked");
});

Q24. Change CSS using JS.

box.style.color = "red";

Q25. setTimeout example.

setTimeout(()=>{
  console.log("Done");
},1000);

Q41. What is closure?

A function that remembers outer variables.

Q42. Promise example.

new Promise((resolve,reject)=>{
  resolve("Done");
});

Q43. Async function.

async function getData(){}

Q44. Await usage.

await fetch(url);

Q45. Fetch API.

fetch(url)
.then(res=>res.json());