Frontend Developer

How would you design a scalable and responsive UI for a global e-commerce platform? How would you design a notification system for a web app?

You're given a simple web page with the following HTML and CSS:

HTML:

<div class="container">    

<button id="hidden-btn">Click Me</button>

</div>

CSS:

.container {    

width: 200px;    

height: 200px;    

background-color: light-blue;    

position: relative;    

overflow: hidden;

}

#hidden-btn {    

position: absolute;    

top: -50px;    

left: -50px;    

width: 100px;    

height: 30px;

background-color: coral;    

color: white;    

border: none;    

cursor: pointer;

}

The Puzzle

The button (#hidden-btn) is hidden outside the bounds of the container due to the overflow: hidden property.

Constraints:

• You cannot modify the HTML or CSS directly.
• Write a JavaScript solution to make the button fully visible within the container, centered both horizontally and vertically, and ensure it is clickable.

You are given a string 'STR'. The string contains [a-z] [A-Z] [0-9] [special characters]. You have to find the reverse of the string.

For example:

 If the given string is: STR = "abcde". You have to print the string "edcba".

follow up:

Try to solve the problem in O(1) space complexity. 

Given an input string S and two characters c1 and c2, you need to replace every occurrence of character c1 with character c2 in the given string.

You are given a string ('STR') of length 'N'. Find the longest palindromic substring. If there is more than one palindromic substring with the maximum length, return the one with the smaller start index.

Note:

A substring is a contiguous segment of a string.

For example : The longest palindromic substring of "ababc" is "aba", since "aba" is a palindrome and it is the longest substring of length 3 which is a palindrome, there is another palindromic substring of length 3 is "bab" since "aba" starting index is less than "bab", so "aba" is the answer.

Which of the following is used to uniquely identify a row in a table?
a) Foreign Key
b) Primary Key
c) Unique Key
d) Composite Key

What is the default isolation level in most relational databases?
a) Read Uncommitted
b) Read Committed
c) Repeatable Read
d) Serializable

You're given a simple web page with the following HTML and CSS:

HTML:

<div class="parent">

   <div class="child-1">Child 1</div>

   <div class="child-2">Child 2</div>

</div>

CSS:

.parent {

   width: 300px;

   height: 300px;

   position: relative;

   background-color: lightgray;

}

.child-1 {

   position: absolute;

   width: 150px;

   height: 150px;

   top: 50px;

   left: 50px;

   background-color: coral;

   z-index: 10;

}

.child-2 {

   position: absolute;

   width: 150px;

   height: 150px;

   top: 100px;

   left: 100px;

   background-color: skyblue;

   z-index: 5;

}

The Puzzle

Current Behavior:

When you load the page, Child 1 is displayed on top of Child 2 because of the z-index values.

Your Task:

Without changing the z-index values, HTML, or structure, make Child 2 appear on top of Child 1.

Rules:

• You cannot modify the z-index values.
• You cannot edit the HTML structure.
• You cannot move the elements in the DOM.

What is the primary purpose of the CSS box-sizing property?
a) To set the width and height of elements
b) To control the padding and margin of elements
c) To include padding and border in the element's total width and height
d) To change the box model to flexbox

Which of the following is NOT a valid JavaScript data type?
a) Undefined
b) Object
c) Function
d) Character

In JavaScript, which of the following methods can be used to add a new element to an array?
a) array.push()
b) array.add()
c) array.insert()
d) array.append()

What does the useEffect hook in React do?
a) It manages state in a functional component
b) It triggers a side effect in a component
c) It renders components based on state changes
d) It optimizes component rendering performance

Which of the following is the correct syntax for importing a component in React?
a) import { Component } from 'react';
b) import React from 'component';
c) import { Component } from 'React';
d) import React.Component from 'react';