Mam slider z buttonami , jak zrobić żeby sam się zmieniał (onload)po np 4 sekundach po załadowaniu strony

Question

Slider zmienia się po wciśnięciu buttona, ale chciałabym żeby tez sam sie zmieniał pook. 4 sek od załadowania strony.

<section id="hero">
  
    <div class="hero-container" data-aos="fade-up">
      <div class="slideshow-container">
      <div class="mySlides">
      <img src="assets/img/favicon.png">
      <h1>Technical Diagnostic Center</h1>
      <h2>For Marine, Oil&Gas and Land Industry</h2>
      <a href="#services" class="btn-get-started scrollto"><i class="bx bx-chevrons-down"></i></a>
      </div>
      <div class="mySlides">
        <img id="news" src="assets/img/news.png" width="250" height="250">
        <br></br>
        <h1>Our news</h1>
        <a href="" class="btn-get-started scrollto"><i class="bx bx-chevrons-down"></i></a>
        </div>
     
  <a class="prev" onclick="plusSlides(-1)">&#10094;</a>
  <a class="next" onclick="plusSlides(1)">&#10095;</a>
    </div>
  </div>
  <div class="dots">
  <div style="text-align: :center">
    <span class="dot" onclick="currentSlide(1)"></span>
    <span class="dot" onclick="currentSlide(2)"></span>
  </div>
  </div>
  </section>

 <script>
    var slideIndex = 1;
    showSlides(slideIndex);
    
    function plusSlides(n) {
      showSlides(slideIndex += n);
    }
    
    function currentSlide(n) {
      showSlides(slideIndex = n);
    }
    
    function showSlides(n) {
      var i;
      var slides = document.getElementsByClassName("mySlides");
      var dots = document.getElementsByClassName("dot");
      if (n > slides.length) {slideIndex = 1}    
      if (n < 1) {slideIndex = slides.length}
      for (i = 0; i < slides.length; i++) {
          slides[i].style.display = "none";  
      }
      for (i = 0; i < dots.length; i++) {
          dots[i].className = dots[i].className.replace(" active", "");
      }
      slides[slideIndex-1].style.display = "block";  
      dots[slideIndex-1].className += " active";
    }
    </script>

 

Answer 1

Możesz użyć zdarzenia window.onload i za jego pomocą wywołać metodę setInterval()

np.

window.onload = function() {
  setInterval(plusSlides, 4000, 1);
};

 

 

P.S. Może zamiast

dots[i].className = dots[i].className.replace(" active", "");

dots[slideIndex-1].className += " active";

użyj  classList , np.

dots[i].classList.remove("active");
 
dots[slideIndex-1].classList.add("active");

 

Comments

zapis jest bez różnicy, bo i tak JIT to zoptymalizuje, chyba że mowa czysto o czytelności.

---

Dlatego napisałem "może", głownie chodzi o czytelność kodu, różnicę będzie widać gdy zastosowanie będzie takie

element.classList.add("class1", "class2", "class3");

element.classList.remove("class1", "class3");

 

Difference between classList and className

 

Using "classList", you can add or remove a class without affecting any others the element may have. But if you assign "className", it will wipe out any existing classes while adding the new one (or if you assign an empty string it will wipe out all of them).

 

Assigning "className" can be a convenience for cases where you are certain no other classes will be used on the element, but I would normally use the "classList" methods exclusively.

 

And "classList" also has handy "toggle" and "replace" methods.

 

no i

classList.add(class1, class2, ...)    

 

Adds one or more class names to an element.
If the specified class already exist, the class will not be added

 

<div id="class_name">className</div>
<button id="class_name_plus">+ active</button>

<div id="class_list">classList</div>
<button id="class_list_plus">+ active</button>

div {
  margin-top: 1em;
}
.active {
  font-weight: bold;
}

const class_name = document.querySelector('#class_name');

const button_class_name = document.querySelector('#class_name_plus');
button_class_name.addEventListener('click', () => {
  class_name.className += " active";
  class_name.textContent = 'className - ' + class_name.className;
});

const class_list = document.querySelector('#class_list');

const button_class_list = document.querySelector('#class_list_plus');
button_class_list.addEventListener('click', () => {
  class_list.classList.add("active");
  class_list.textContent = 'classList - ' + class_list.className;
});