Grey out screen on form submit until new page load

Add just under the page <body> tag – Normal

<body>
  <!------------------------------------->
  <!---- PAGE LOADING COVER ELEMENT ----->
  <!------------------------------------->
  <div id="page_loading_cover"></div>
  <div id="page_loading_cover_animated_icon"></div>
  <script>
    /* Remove greyed loading page cover once page has finished loading */
      //$(window).on('load', function() {      //Don't use this as it won't trigger if user presses their back button
      $(window).on('pageshow', function() {    //'pageshow' triggers for page load and back button back to page
       $("#page_loading_cover").hide();
      page_loading_cover.style.visibility = "hidden" ;
      page_loading_cover_animated_icon.style.visibility = "hidden" ;
    });

    /* Turn on greyed loading page cover */
    function DisablePageUntilReloaded() {
      $("#page_loading_cover").show();
      page_loading_cover.style.visibility = "visible" ;
      page_loading_cover_animated_icon.style.visibility = "visible" ;
    }
  </script>

Add just under the page <body> tag – WordPress

(Same but needs the ‘$’ changed to ‘jQuery’ or you get “TypeError: $ is not a function” console errors)

<body>
  <!------------------------------------->
  <!---- PAGE LOADING COVER ELEMENT ----->
  <!------------------------------------->
  <div id="page_loading_cover"></div>
  <div id="page_loading_cover_animated_icon"></div>
  <script>
    /* Remove greyed loading page cover once page has finished loading */
    jQuery(window).on('load', function() {
       jQuery("#page_loading_cover").hide();
      page_loading_cover.style.visibility = "hidden" ;
      page_loading_cover_animated_icon.style.visibility = "hidden" ;
    });

    /* Turn on greyed loading page cover */
    function DisablePageUntilReloaded() {
      jQuery("#page_loading_cover").show();
      page_loading_cover.style.visibility = "visible" ;
      page_loading_cover_animated_icon.style.visibility = "visible" ;
    }
  </script>

Create a style for it

/*----- PAGE LOADING COVER ELEMENT -----*/
#page_loading_cover {
  position: fixed;
  height: 100%;
  width: 100%;
  top:0;
  left: 0;
  background: #000;
  opacity: 0.5;
  z-index:9999;
  visibility: hidden;  /*Include this so element will only be shown when DisablePageUntilReloaded() is called*/
}

/*Spinning icon*/
#page_loading_cover_animated_icon {
  border: 12px solid #f3f3f3;
  border-radius: 50%;
  border-top: 12px solid #3498db;
  width: 80px;
  height: 80px;
  -webkit-animation: animated_icon_spin 2s linear infinite; /* Safari */
  animation: animated_icon_spin 2s linear infinite;
  
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -40px;
  margin-left: -40px;
  z-index:9999;
  visibility: hidden;  /*Include this so element will only be shown when DisablePageUntilReloaded() is called*/
}
/* Safari */
@-webkit-keyframes animated_icon_spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes animated_icon_spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

For any form submit you want to trigger it use onsubmit

<form id="my_form" onsubmit="return DisablePageUntilReloaded()" action="\my_page.php" method="POST">

If you have any onchange submit form elements you will need to call the function separately as onchange .submit won’t trigger it:

<input type="checkbox" name="MyCheckbox" value="1" onchange="DisablePageUntilReloaded(); my_form.submit();" >

For any html link you want to trigger it use onclick

<a href="/my_page.php" onclick="DisablePageUntilReloaded()" >Click me</a>

Feel free to comment if you can add help to this page or point out issues and solutions you have found. I do not provide support on this site, if you need help with a problem head over to stack overflow.

JavaScript Development