如何跨多个页面设置暗模式主题？

Question

I'm trying to implement a dark mode across my website which has 3 different pages. I made 3 separate javascript files to each page and copied the dark mode code to each one. Now I want to save the preference so that the user doesn't have to keep clicking the dark mode feature every single time they go to a different part of the site. This is what I have that changes it to dark mode. I've seen answers using localStorage but I'm still new to JS so I'm having trouble implementing it. Should I have only one javascript file for all 3 pages or keep it separate files?

   <label class="switch">
   <input type="checkbox" id="darkmode">
   <span class="slider round"></span>
   </label>


let checkbox = document.getElementById("darkmode");
let body = document.getElementById('body')

checkbox.addEventListener( 'change', function() {
if(this.checked) {
    body.classList.add('dark')
} else {
    body.classList.remove('dark')     
}
});

Answer 1

In order to achieve this, you can do the following:

• On each page do the following on change:

    checkbox.addEventListener( 'change', function() {
         localStorage.setItem('dark',this.checked);
         if(this.checked) {
              body.classList.add('dark')
         } else {
              body.classList.remove('dark')     
         }
    });

• And on load of each page, do the following:

    if(localStorage.getItem('dark')) {
         body.classList.add('dark');
    }

Answer 2

A simple trick is to use the window.localstorage() or cookies(), this will help you to make this functionality easily.
For more information, you can see this article MDN Window.localStorage & MDN cookies.Cookie

Practical example always help us 100%,
This is a better way to do this stuff. https:// codepen.io/Md_Tahazzot/pen/xxKLmJa