Question 189689 in Html Question posted in
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Html – Custom javascript button to change body background and font color

Note: not a duplicated because this is a custom made code and no other answer is answering my question, also because this is only javascript and not Jquery based

After reading hundreds of other posts and answers I decided to create a simple function instead of complicated/advanced ones, using just javascript. The problem is that I just started to learn javascript yesterday 🙂

What I want:

I want users to click on a single toggle button to turn dark mode on/off without complications in the code but just to save the value in localStorage and/or retrieve the chosen values from localStorage

The colors are just 2:

Dark mode is: body background #101010 and body font color if #FFFFFF

Light mode is: body background #FFFFFF and body font color if #101010

What I have

HTML

<button class="change" value="on">Dark mode is on</a>
<button class="change" value="off">Dark mode is off</a>
#would be nice with a single toggle button

Javascript

var document.querySelector(".change")
var body = document.getElementsByTagName("body")

btn.addEventListener("click", (e) => {
if (body[0].style.backgroundColor === "on") {
body[0].style.backgroundColor = "#101010"
body[0].style.color = "#FAFAFA"

} else {
body[0].style.backgroundColor = "#FAFAFA"
body[0].style.color = "#101010"

}
localStorage.setItem("bgColor", body[0].style.backgroundColor)
localStorage.setItem("textColor", body[0].style.color)
})
body[0].style.backgroundColor = localStorage.getItem("bgColor")
body[0].style.color = localStorage.getItem("textColor")

What I need

To make it save the chosen colors by the user and remember them with localstorage

To know if it is possible to make the button toggle with the text:
Dark mode is on/Dark mode is off

I created this Codepen with the code
https://codepen.io/familias/pen/gOQMrjX

Tags:

2

Answers


  1. 0

    This should work fine now, I just added on to your code.

    The selected (mode)colors by the user will be saved in localStorage and retrieved when the page is loaded. Additionally I updated the CSS to include a .dark-mode class that applies the dark mode styles to the body element.

    html
<button id="toggleBtn">Dark mode is on</button>

    javascript

    var toggleBtn = document.getElementById("toggleBtn");
var body = document.getElementsByTagName("body")[0];

toggleBtn.addEventListener("click", function() {
  var bgColor, textColor;

  if (body.classList.contains("dark-mode")) {
    body.classList.remove("dark-mode");
    toggleBtn.textContent = "Dark mode is on";
    bgColor = "#FFFFFF";
    textColor = "#101010";
  } else {
    body.classList.add("dark-mode");
    toggleBtn.textContent = "Dark mode is off";
    bgColor = "#101010";
    textColor = "#FFFFFF";
  }

  body.style.backgroundColor = bgColor;
  body.style.color = textColor;

  // Save the chosen colors to localStorage
  localStorage.setItem("bgColor", bgColor);
  localStorage.setItem("textColor", textColor);
});

// Retrieve saved colors from localStorage
var savedBgColor = localStorage.getItem("bgColor");
var savedTextColor = localStorage.getItem("textColor");

if (savedBgColor && savedTextColor) {
  body.style.backgroundColor = savedBgColor;
  body.style.color = savedTextColor;

  if (savedBgColor === "#101010" && savedTextColor === "#FFFFFF") {
    body.classList.add("dark-mode");
    toggleBtn.textContent = "Dark mode is off";
  }
}

    css
body {
  margin: 0;
  height: 100%;
}

.dark-mode {
  background-color: #101010;
  color: #FFFFFF;
}
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  2. 0

    Newb here also, buy I’ll try to help you.

    I suggest using a checkbox. You can use CSS to make a slider button. Follow below what you need with my comments.

    window.addEventListener('DOMContentLoaded', function() {
    var checkbox = document.getElementById('change'); //Get the status os the checkbox
  
    checkbox.addEventListener('change', function() { //Checks if the status changed
      if (checkbox.checked) {
        document.body.classList.add('dark-theme'); //Uses the dark-theme that is in the CSS file.
        localStorage.setItem('theme', 'dark'); //Saves the "theme" in local storage
      } else {
        document.body.classList.remove('dark-theme'); //Goes back to normal model in the CSS file
        localStorage.setItem('theme', 'light');  //Saves the "theme" in local storage
      }
    });
  
    var savedTheme = localStorage.getItem('theme'); //When you load the page, it will check which 'theme' is stored. If it is normal, it does nothing, if it's dark, checks the checkbox and uses the dark-theme in CSS.
    if (savedTheme === 'dark') {
      checkbox.checked = true;
      document.body.classList.add('dark-theme');
    }
  });
    /* The switch - the box around the slider */
.switch {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 34px;
}

/* Hide default HTML checkbox */
.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

/* The slider */
.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

<!-- begin snippet: js hide: false console: true babel: false -->
    <label for="change">Dark mode</label>
<label class="switch">
    <input type="checkbox" id="change">
    <span class="slider round"></span>
  </label>
    input:checked + .slider:before {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}

/* Rounded sliders */
.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}

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