我如何将所有这些代码存储在一个变量中

Question

How can i keep all these codes in a variable? I want to call this codes in another place. I want to add a click event on this slideShow menu. It's easy if i write all those codes in another click event function. But i don't want to do that, i want to call all this codes in a click event by uscing a variable

function change() {
  if (document.getElementsByClassName("sliderItems")[0].classList.contains("active")) {
    document.getElementsByClassName("sliderItems")[1].classList.add("active");
    document.getElementsByClassName("sliderItems")[0].classList.remove("active");
  } else if (document.getElementsByClassName("sliderItems")[1].classList.contains("active")) {
    document.getElementsByClassName("sliderItems")[2].classList.add("active");
    document.getElementsByClassName("sliderItems")[1].classList.remove("active");

  } else if (document.getElementsByClassName("sliderItems")[2].classList.contains("active")) {
    document.getElementsByClassName("sliderItems")[3].classList.add("active");
    document.getElementsByClassName("sliderItems")[2].classList.remove("active");

  } else if (document.getElementsByClassName("sliderItems")[3].classList.contains("active")) {
    document.getElementsByClassName("sliderItems")[4].classList.add("active");
    document.getElementsByClassName("sliderItems")[3].classList.remove("active");

  } else if (document.getElementsByClassName("sliderItems")[4].classList.contains("active")) {
    document.getElementsByClassName("sliderItems")[1].classList.add("active");
    document.getElementsByClassName("sliderItems")[4].classList.remove("active");
  }
}
setInterval(change, 2000);

Answer 1

I don't sure what you mean with codes, I think you mean the array of sliderItems, if this is what you mean is very easy.

var sliderItems = document.getElementsByClassName('sliderItems');

sliderItems[0].classList.add('active');

The big advantage of using a variable to store a DOM element is better performance than searching the element every single time you want to use it.

Answer 2

just assign setInterval(change, 2000) to a variable and use it

add to your script

var listenChange = setInterval(change, 2000)

use it in your html

<button onclick="listenChange()">Button1</Button>