JavaScript: Display a random image by clicking on a button

Last update on May 30 2022 10:00:14 (UTC/GMT +8 hours)

JavaScript DOM: Exercise-11 with Solution

Write a JavaScript program to display a random image (clicking on a button) from the following list.

Sample Image information :

"https://farm4.staticflickr.com/3691/11268502654_f28f05966c_m.jpg", width: "240", height: "160"
"https://farm1.staticflickr.com/33/45336904_1aef569b30_n.jpg", width: "320", height: "195"
"https://farm6.staticflickr.com/5211/5384592886_80a512e2c9.jpg", width: "500", height: "343"

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Display a random image.</title>
<style type="text/css">
body {margin-top: 30px;}
</style> 
</head>
<body>
<div>
<button id="jsstyle" 
onclick="display_random_image();">Show Image</button> 
</div>
</body>
</html>

JavaScript Code:

function display_random_image() 
{
     var theImages = [{
        src: "https://farm4.staticflickr.com/3691/11268502654_f28f05966c_m.jpg",
        width: "240",
        height: "160"
    }, {
        src: "https://farm1.staticflickr.com/33/45336904_1aef569b30_n.jpg",
        width: "320",
        height: "195"
    }, {
        src: "https://farm6.staticflickr.com/5211/5384592886_80a512e2c9.jpg",
        width: "500",
        height: "343"
    }];
    
    var preBuffer = [];
    for (var i = 0, j = theImages.length; i < j; i++) {
        preBuffer[i] = new Image();
        preBuffer[i].src = theImages[i].src;
        preBuffer[i].width = theImages[i].width;
        preBuffer[i].height = theImages[i].height;
    }
   
// create random image number
  function getRandomInt(min,max) 
    {
      //  return Math.floor(Math.random() * (max - min + 1)) + min;
    
imn = Math.floor(Math.random() * (max - min + 1)) + min;
    return preBuffer[imn];
    }  

// 0 is first image,   preBuffer.length - 1) is  last image
  
var newImage = getRandomInt(0, preBuffer.length - 1);
 
// remove the previous images
var images = document.getElementsByTagName('img');
var l = images.length;
for (var p = 0; p < l; p++) {
    images[0].parentNode.removeChild(images[0]);
}
// display the image  
document.body.appendChild(newImage);
}

Sample Output:

Flowchart:

Live Demo:

See the Pen javascript-dom-exercise-11 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04