I have this simple blade.php with the following code:
<script type="javascript">
    $("#loading-button").click(
        function () {
                $("#loading-overlay").show();
        }
    );
</script>
<style type="text/css">
    #loading-screen {
        background: url({{asset('storage/loading.gif')}}) center center no-repeat;
        height: 100%;
        z-index: 20;
    }
    #loading-overlay {
        background: #e9e9e9;
        display: none;
        position: absolute;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
        opacity: 0.5;
    }
</style>
<div id="loading-overlay">
    <div id="loading-screen"> LOADING...  </div>
</div>
In the other layout, I am loding jquery-3.2.1 and in my main page I am extending the main layout (where jquery is loaded) and including the loading layout from above. The page source looks like this after rendering (Chrome page source):
<script type="javascript">
    $("#loading-button").click(
        function () {
                $("#loading-overlay").show();
        }
    );
</script>
<style type="text/css">
    #loading-screen {
        background: url(http://localhost:8000/storage/loading.gif) center center no-repeat;
        height: 100%;
        z-index: 20;
    }
    #loading-overlay {
        background: #e9e9e9;
        display: none;
        position: absolute;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
        opacity: 0.5;
    }
</style>
<div id="loading-overlay">
    <div id="loading-screen"> LOADING...  </div>
</div>
<button id="loading-button">TEST</button>
If I copy paste the code in JSFiddle, it works. It doesn't have the image, but that is not relevant, as it is stored locally, but the overlay displays as expected.
The main layout has this in it:
<script src="http://localhost:8000/js/jquery-3.2.1.min.js"></script>
<script src="http://localhost:8000/js/bootstrap.min.js"></script>
CONSOLE ERROR:
bootstrap.min.js:7 Uncaught Error: Bootstrap tooltips require Tether (http://tether.io/)
    at bootstrap.min.js:7
    at bootstrap.min.js:7
    at bootstrap.min.js:7
 
     
    