Disable page while loading Progress bar

Question

Good afternoon, you guys! I have a progress bar which is used to indicate the loading of the page. It is implemented through css and js. I would like to know how to disable the page body until the loading is complete (progress bar). Follow bar code.

Hug!

/*! pace 1.0.0 */
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.pace {
  -webkit-pointer-events: none;
  pointer-events: none;

  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
}

.pace-inactive {
  display: none;
}

.pace .pace-progress {
  background: #29d;
  position: fixed;
  z-index: 2000;
  top: 0;
  right: 100%;
  width: 100%;
  height: 5px;
}

Answer 1

Good friend the code of the "bar" is not very useful since this "minificado" as to Pace.js the library has option to monitor the loading of certain elements as shown in documentation.

Now if what you are in fact does not show the content while there is not the full upload I leave you two answers:

---

Short answer: use window.onload reference and examples W3schools.

---

Correct answer:

Block user access to page content (body) or parts of the content because there has been no complete loading is not such an unusual technique but is not recommended use "obstructive" aspects to do so because they denigrate the user’s experience with the application.

The easiest (and least recommended) method would be to apply a class with property display: none in body and after full loading via javascript (read: window.onload) modify this class to display: block or remove it.

Example: jsfiddle

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <style type="text/css">
      .none{
         display: none;
      }
  </style>
</head>
<body class="none">
  <h1>Hello World!</h1>

  <script type="text/javascript">
    var showBody = function(){
        document.getElementsByTagName("BODY")[0].removeAttribute("class");
    };

    // após a página carregar tudo
    window.onload = showBody();
  </script>
</body>
</html>

If you already have the attribute class in his body and do not want to remove can use setAttribute to rewrite the attributes of class or use artifices such as removeClass to explicitly remove the item.

Like this you could show a background image, a loading message or an icon while the content is still loading bad for this class with display: none should not be attributed to body but rather the other element on the page as a div used as "container" of the application and the element with the "message|image" would be displayed by default and removed later as in this example in jsfiddle.

However in both examples are practical obstructive that may be detrimental to the user’s experience since the features of your application may take a while to load or if a fatal error occurs in the execution of the script so that the page is not viewed because the class was not removed or modified by script.

Following this "technique" the "most correct" approach would be to make available the essential content part of the page immediately and to make a dynamic upload of the other elements of the page servingblocks thus making them available only after loading their dependencies... of course this is more applied to architecture and design orientation than simply a code since numerous techniques and methodologies are necessary to arrive at this approach "more correct".

There are many libraries that help in this direction (dynamic loading).

To sharpen your curiosity I leave the recommendation of this Preloadjs is very solid and easy to work maybe it will help to understand and arrive at the result you expect.