code-boxx/0-JS-HTML-LOADING.MD

## 0-JS-HTML-LOADING.MD

      
    Raw
  

              0-JS-HTML-LOADING.MD
            
          
    JAVASCRIPT HTML LOADING SPINNER UNTIL PAGE LOAD

https://code-boxx.com/show-loading-spinner-until-page-loads/
IMAGE


LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1a-load-order.html
<!DOCTYPE html>
<html>
  <head>
    <title>Page Load Order</title>

    <!-- (A1) LOADING SPINNER -->
    <link rel="stylesheet" href="1b-load-spinner.css">
    <script src="1c-load-spinner.js"></script>
  </head>
  <body>
    <!-- (A2) LOADING SPINNER -->
    <div id="loading"></div>

    <!-- (B) REST OF THE PAGE -->
    <p>YOUR CONTENT HERE</p>

    <!-- (C) LOAD JS/CSS LAST -->
    <script>
    // JUST RUN LOADER() IF NO SCRIPTS TO LOAD
    window.addEventListener("DOMContentLoaded", () => loader([
      "my.CSS", "my.js", "https://cdnjs.cloudflare.com/ajax/libs/WHATEVER.JS"
    ]));
    </script>
  </body>
</html>

## 1b-load-spinner.css
#loading {
  /* (A1) COVER FULL PAGE */
  position: fixed;
  top: 0; left: 0; z-index: 999;
  width: 100vw; height: 100vh;

  /* (A2) SPINNER IMAGE */
  background-color: black;
  background-image: url("ajax-loader.gif");
  background-position: center;
  background-repeat: no-repeat;
}

## 1c-load-spinner.js
function loader (all) {
  // (A) ALL LOADED - REMOVE SPINNER
  var total = 0, loaded = 0, s,
  ready = () => {
    loaded++;
    if (loaded>=total) { document.getElementById("loading").remove(); }
  };

  // (B) CREATE <LINK><SCRIPT>
  if (Array.isArray(all)) {
    total = all.length;
    all.forEach(url => {
      // (B1) CSS FILE - <LINK>
      if (url.toLowerCase().includes(".css")) {
        s = document.createElement("link");
        s.rel = "stylesheet";
        s.href = url;
        s.onload = ready; s.onerror = ready;
      }

      // (B2) JS FILE - <SCRIPT ASYNC>
      else {
        s = document.createElement("script");
        s.async = true;
        s.src = url;
        s.onload = ready; s.onerror = ready;
      }
      document.head.appendChild(s);
    });
  }

  // (C) JUST START IF NO SCRIPTS TO LOAD
  else { ready(); }
}

## 2a-ajax-load.html
<!DOCTYPE html>
<html>
  <head>
    <title>AJAX Load</title>

    <!-- (A) CSS & SCRIPTS -->
    <link rel="stylesheet" href="2b-styles.css">
    <script src="2c-loader.js"></script>
    <script>
    window.onload = () => loader("2d-content.html");
    </script>
  </head>
  <body>
    <!-- (B) LOADING SPINNER -->
    <div id="loading" class="load"></div>

    <!-- (C) HTML PAGE AS USUAL -->
    <header>Header</header>
    <main id="main"></main>
    <footer>Footer</footer>
  </body>
</html>

## 2b-styles.css
#loading {
  /* (A1) COVER FULL PAGE */
  position: fixed;
  top: 0; left: 0; z-index: 999;
  width: 100vw; height: 100vh;

  /* (A2) SPINNER IMAGE */
  background-color: rgba(0, 0, 0, 0.5);
  background-image: url("ajax-loader.gif");
  background-position: center;
  background-repeat: no-repeat;

  /* (A3) HIDDEN BY DEFAULT */
  display: none;
}

/* (A4) SHOW LOADING */
#loading.load { display: block; }

/* (X) DUMMY PAGE LAYOUT */
* {
  font-family: arial, sans-serif;
  box-sizing: border-box;
}
body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding: 0; margin: 0;
}
main { flex-grow: 1; }
header, main, footer { padding: 10px; }
header { background: #ffd6d6; }
footer { background: #d6e5ff; }

## 2c-loader.js
function loader (url, loaded) {
  // (A) GET HTML ELEMENTS
  var main = document.getElementById("main"),
      loading = document.getElementById("loading");

  // (B) LOADING SPINNER
  loading.classList.add("load");

  // (C) AJAX LOAD PAGE
  fetch(url)
  .then(res => res.text())
  .then(txt => {
    main.innerHTML = txt;
    if (typeof loaded == "function") { loaded(); }
  })
  .finally(() => loading.classList.remove("load"));
}

## 2d-content.html
<h1>Hello World</h1>
<p>It works!</p>
	<!DOCTYPE html>
	<html>
	<head>
	<title>Page Load Order</title>

	<!-- (A1) LOADING SPINNER -->
	<link rel="stylesheet" href="1b-load-spinner.css">
	<script src="1c-load-spinner.js"></script>
	</head>
	<body>
	<!-- (A2) LOADING SPINNER -->
	<div id="loading"></div>

	<!-- (B) REST OF THE PAGE -->
	<p>YOUR CONTENT HERE</p>

	<!-- (C) LOAD JS/CSS LAST -->
	<script>
	// JUST RUN LOADER() IF NO SCRIPTS TO LOAD
	window.addEventListener("DOMContentLoaded", () => loader([
	"my.CSS", "my.js", "https://cdnjs.cloudflare.com/ajax/libs/WHATEVER.JS"
	]));
	</script>
	</body>
	</html>
	#loading {
	/* (A1) COVER FULL PAGE */
	position: fixed;
	top: 0; left: 0; z-index: 999;
	width: 100vw; height: 100vh;

	/* (A2) SPINNER IMAGE */
	background-color: black;
	background-image: url("ajax-loader.gif");
	background-position: center;
	background-repeat: no-repeat;
	}
	function loader (all) {
	// (A) ALL LOADED - REMOVE SPINNER
	var total = 0, loaded = 0, s,
	ready = () => {
	loaded++;
	if (loaded>=total) { document.getElementById("loading").remove(); }
	};

	// (B) CREATE <LINK><SCRIPT>
	if (Array.isArray(all)) {
	total = all.length;
	all.forEach(url => {
	// (B1) CSS FILE - <LINK>
	if (url.toLowerCase().includes(".css")) {
	s = document.createElement("link");
	s.rel = "stylesheet";
	s.href = url;
	s.onload = ready; s.onerror = ready;
	}

	// (B2) JS FILE - <SCRIPT ASYNC>
	else {
	s = document.createElement("script");
	s.async = true;
	s.src = url;
	s.onload = ready; s.onerror = ready;
	}
	document.head.appendChild(s);
	});
	}

	// (C) JUST START IF NO SCRIPTS TO LOAD
	else { ready(); }
	}
	function loader (url, loaded) {
	// (A) GET HTML ELEMENTS
	var main = document.getElementById("main"),
	loading = document.getElementById("loading");

	// (B) LOADING SPINNER
	loading.classList.add("load");

	// (C) AJAX LOAD PAGE
	fetch(url)
	.then(res => res.text())
	.then(txt => {
	main.innerHTML = txt;
	if (typeof loaded == "function") { loaded(); }
	})
	.finally(() => loading.classList.remove("load"));
	}