我的 javascript queryselectorall 未按预期捕获第二个 class 名称

Question

I have two images with different classes but I want the same JavaScript to be applied to both. This javascript basically allows for a slideshow by clicking on the button, but this only works for the images with the mySlides class, not the albums class. Take a look:

 var slideIndex = 1; showDivs(slideIndex); function plusDivs(n) { showDivs(slideIndex += n); } function showDivs(n) { var i; var x = document.querySelectorAll(".mySlides, .albums"); if (n > x.length) { slideIndex = 1 } if (n < 1) { slideIndex = x.length }; for (i = 0; i < x.length; i++) { x[i].style.display = "none"; } x[slideIndex - 1].style.display = "block"; }

 <link href="https://www.w3schools.com/w3css/4/w3.css" rel="stylesheet"/> <div class="inner"> <img class="mySlides" src="./imgs/IMG_1552.JPG"> <img class="mySlides" src="./imgs/IMG_0915.jpg"> <button class="w3-button w3-display-left" onclick="plusDivs(-1)">&#10094;</button> <button class="w3-button w3-display-right" onclick="plusDivs(+1)">&#10095;</button> </div> <div class="inner"> <img class="albums" src="./imgs/travis.jpg"> <img class="albums" src="./imgs/killy.jpg"> <button class="w3-button w3-display-left" onclick="plusDivs(-1)">&#10094;</button> <button class="w3-button w3-display-right" onclick="plusDivs(+1)">&#10095;</button> </div>

The buttons are supposed to move to the next image eg from "travis.jpg" to "killy.jpg" but it only works for the mySlides class and not the albums class

Answer 1

The issue lies in var x = document.querySelectorAll(".mySlides, .albums"); As you have to understand that this query selects all the 4 elements if you want to do for the second element of both classes you would have to go with

var x = document.querySelectorAll(".mySlides");
var y = document.querySelectorAll(" .albums");

and run the further logic on both var seperately