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# Binary Search Visualization using JavaScript

GUI(Graphical User Interface) helps in better understanding than programs. In this article, we will visualize Binary Search using JavaScript. We will see how the elements are being traversed in Binary Search until the given element is found. We will also visualize the time complexity of Binary Search.

Reference:

Approach:

• First, we will generate a random array using Math.random() function and then sort it using sort() function.
• Different color is used to indicate which element is being traversed at current time.
• Since the algorithm performs the operation very fast, the setTimeout() function has been used to slow down the process.
• New array can be generated by pressing the “Ctrl+R” key.
• The searching is performed using BinarySearch() function.

Example:

Before Searching

After Searching

Below is the program to visualize the Binary Search algorithm.

Filename: index.html

## HTML



Binary Search

Filename: style.css

## CSS

 * {  margin: 0px;  padding: 0px;  box-sizing: border-box;} .header {  font-size: 35px;  text-align: center;} #array {  background-color: white;  height: 305px;  width: 598px;  margin: auto;  position: relative;  margin-top: 64px;} .block {  width: 28px;  background-color: #6b5b95;  position: absolute;  bottom: 0px;  transition: 0.2s all ease;} .block_id {  position: absolute;  color: black;  margin-top: -20px;  width: 100%;  text-align: center;}

Filename: script.js

## Javascript

 var container = document.getElementById("array"); // Function to generate the array of blocksfunction generatearray() {   // Creating an array  var arr = [];   // Filling array with random values  for (var i = 0; i < 20; i++) {    // Return a value from 1 to 100 (both inclusive)    var val = Number(Math.ceil(Math.random() * 100));    arr.push(val);  }   // Sorting Array in ascending order  arr.sort(function (a, b) {    return a - b;  });   for (var i = 0; i < 20; i++) {    var value = arr[i];     // Creating element div    var array_ele = document.createElement("div");     // Adding class 'block' to div    array_ele.classList.add("block");     // Adding style to div    array_ele.style.height = `\${value * 3}px`;    array_ele.style.transform = `translate(\${i * 30}px)`;     // Creating label element for displaying    // size of particular block    var array_ele_label = document.createElement("label");    array_ele_label.classList.add("block_id");    array_ele_label.innerText = value;     // Appending created elements to index.html    array_ele.appendChild(array_ele_label);    container.appendChild(array_ele);  }} // Asynchronous BinarySearch functionasync function BinarySearch(delay = 300) {  var blocks = document.querySelectorAll(".block");  var output = document.getElementById("text");   //Extracting the value of the element to be searched  var num = document.getElementById("fname").value;   //Colouring all the blocks violet  for (var i = 0; i < blocks.length; i += 1) {    blocks[i].style.backgroundColor = "#6b5b95";  }   output.innerText = "";   // BinarySearch Algorithm   var start = 0;  var end = 19;  var flag = 0;  while (start <= end) {    //Middle index    var mid = Math.floor((start + end) / 2);    blocks[mid].style.backgroundColor = "#FF4949";     //Value at mid index    var value = Number(blocks[mid].childNodes[0].innerHTML);     // To wait for .1 sec    await new Promise((resolve) =>      setTimeout(() => {        resolve();      }, delay)    );     //Current element is equal to the element    //entered by the user    if (value == num) {      output.innerText = "Element Found";      blocks[mid].style.backgroundColor = "#13CE66";      flag = 1;      break;    }    //Current element is greater than the element    //entered by the user    if (value > num) {      end = mid - 1;      blocks[mid].style.backgroundColor = "#6b5b95";    } else {      start = mid + 1;      blocks[mid].style.backgroundColor = "#6b5b95";    }  }  if (flag === 0) {    output.innerText = "Element Not Found";  }} // Calling generatearray functiongeneratearray();

Output:

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