Question

I have a tab gallery (from W3Schools) where you can choose an image to show under. I was wondering how to have an active class for the chosen image after I choose. Like when you see it on navbar (this example shows that pages is open). (Home pages about contact) I just need to give the clicked image any class(opacity or color) I tried many things but still new with JavaScript and couldn t achieve what I want:

function myFunction(imgs) {
  var expandImg = document.getElementById("expandedImg");
  var imgText = document.getElementById("imgtext");
  expandImg.src = imgs.src;
  imgText.innerHTML = imgs.alt;
  expandImg.parentElement.style.display = "block";
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial;
}

/* The grid: Four equal columns that floats next to each other */
.column {
  float: left;
  width: 25%;
  padding: 10px;
}

/* Style the images inside the grid */
.column img {
  opacity: 0.8; 
  cursor: pointer; 
}

.column img:hover {
  opacity: 1;
}

/* Clear floats after the columns */
.row:after {
  content: "";
  display: table;
  clear: both;
}

/* The expanding image container */
.container {
  position: relative;
  display: none;
}

/* Expanding image text */
#imgtext {
  position: absolute;
  bottom: 15px;
  left: 15px;
  color: white;
  font-size: 20px;
}

/* Closable button inside the expanded image */
.closebtn {
  position: absolute;
  top: 10px;
  right: 15px;
  color: white;
  font-size: 35px;
  cursor: pointer;
}

<div style="text-align:center">
  <h2>Tabbed Image Gallery</h2>
  <p>Click on the images below:</p>
</div>

<!-- The four columns -->
<div class="row">
  <div class="column">
    <img src="https://picsum.photos/200" alt="Nature" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/222" alt="Snow" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/201" alt="Mountains" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/209" alt="Lights" style="width:100%" onclick="myFunction(this);">
  </div>
</div>

<div class="container">
  <span onclick="this.parentElement.style.display= none " class="closebtn">&times;</span>
  <img id="expandedImg" style="width:100%">
  <div id="imgtext"></div>
</div>

Answer 1

您可以使用。您可使用 event.target,以获取引发听众并相应增加/取消课程的内容:

// get the images that we want to listen for clicks from
let img = document.querySelectorAll(".column img");

// add an event listener to each image
img.forEach(function(elem) {
  // when one of the images is clicked, add the "your-class" class to it and remove the class from any other elements
  elem.addEventListener("click", function(event) {
    // check if any other elements have the class and remove it if some do
    if (document.querySelectorAll(".your-class").length != 0) {
      document.querySelector(".your-class").classList.remove("your-class");
      // if there are no other elements with "your-class" do nothing
    } else {}
    // add "your-class" to the element clicked
    event.target.classList.add("your-class")
  });
});

在以下的法典中,我已经表明了这一点,在点击时,有一把积极形象的边境改为彩色相:

// get the images that we want to listen for clicks from
let img = document.querySelectorAll(".column img");

// add an event listener to each image
img.forEach(function(elem) {
  // when one of the images is clicked, add the border-cyan class to it and remove the class from any other elements
  elem.addEventListener("click", function(event) {
    // check if any other elements have the class and remove it if some do
    if (document.querySelectorAll(".border-cyan").length != 0) {
      document.querySelector(".border-cyan").classList.remove("border-cyan");
      // if there are no other elements with the border cyan class do nothing
    } else {}
    // add the border cyan class to the element clicked
    event.target.classList.add("border-cyan")
  });
});

function myFunction(imgs) {
  var expandImg = document.getElementById("expandedImg");
  var imgText = document.getElementById("imgtext");
  expandImg.src = imgs.src;
  imgText.innerHTML = imgs.alt;
  expandImg.parentElement.style.display = "block";
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial;
}


/* The grid: Four equal columns that floats next to each other */

.column {
  float: left;
  width: 25%;
  padding: 10px;
}


/* Style the images inside the grid */

.column img {
  opacity: 0.8;
  cursor: pointer;
}

.column img:hover {
  opacity: 1;
}


/* Clear floats after the columns */

.row:after {
  content: "";
  display: table;
  clear: both;
}


/* The expanding image container */

.container {
  position: relative;
  display: none;
}


/* Expanding image text */

#imgtext {
  position: absolute;
  bottom: 15px;
  left: 15px;
  color: white;
  font-size: 20px;
}


/* Closable button inside the expanded image */

.closebtn {
  position: absolute;
  top: 10px;
  right: 15px;
  color: white;
  font-size: 35px;
  cursor: pointer;
}

.border-cyan {
  border: 3px solid cyan;
}

<div style="text-align:center">
  <h2>Tabbed Image Gallery</h2>
  <p>Click on the images below:</p>
</div>

<!-- The four columns -->
<div class="row">
  <div class="column">
    <img src="https://picsum.photos/200" alt="Nature" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/222" alt="Snow" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/201" alt="Mountains" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/209" alt="Lights" style="width:100%" onclick="myFunction(this);">
  </div>
</div>

<div class="container">
  <span onclick="this.parentElement.style.display= none " class="closebtn">&times;</span>
  <img id="expandedImg" style="width:100%">
  <div id="imgtext"></div>
</div>

Answer 2

at first you need to find all images and remove class from them
after that add class for clicked image

function myFunction(img) {
  var expandImg = document.getElementById("expandedImg");
  var imgText = document.getElementById("imgtext");
  expandImg.src = img.src;
  imgText.innerHTML = img.alt;
  expandImg.parentElement.style.display = "block";
  img.closest( .row ).querySelectorAll( img ).forEach(img => img.classList.remove( yourClassName ))
  img.classList.add( yourClassName )
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial;
}

/* The grid: Four equal columns that floats next to each other */
.column {
  float: left;
  width: 25%;
  padding: 10px;
}

/* Style the images inside the grid */
.column img {
  opacity: 0.8; 
  cursor: pointer; 
}

.column img:hover {
  opacity: 1;
}

/* Clear floats after the columns */
.row:after {
  content: "";
  display: table;
  clear: both;
}

/* The expanding image container */
.container {
  position: relative;
  display: none;
}

/* Expanding image text */
#imgtext {
  position: absolute;
  bottom: 15px;
  left: 15px;
  color: white;
  font-size: 20px;
}

/* Closable button inside the expanded image */
.closebtn {
  position: absolute;
  top: 10px;
  right: 15px;
  color: white;
  font-size: 35px;
  cursor: pointer;
}

.yourClassName {
border: 1px solid red;
}

<div style="text-align:center">
  <h2>Tabbed Image Gallery</h2>
  <p>Click on the images below:</p>
</div>

<!-- The four columns -->
<div class="row">
  <div class="column">
    <img src="https://picsum.photos/200" alt="Nature" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/222" alt="Snow" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/201" alt="Mountains" style="width:100%" onclick="myFunction(this);">
  </div>
  <div class="column">
    <img src="https://picsum.photos/209" alt="Lights" style="width:100%" onclick="myFunction(this);">
  </div>
</div>

<div class="container">
  <span onclick="this.parentElement.style.display= none " class="closebtn">&times;</span>
  <img id="expandedImg" style="width:100%">
  <div id="imgtext"></div>
</div>

友情链接