How can I create a “Please Wait, Loading…” animation using jQuery?

Question

I would like to place a \"please wait, loading\" spinning circle animation on my site. How should I accomplish this using jQuery?

Answer 1

Most of the solutions I have seen either expects us to design a loading overlay, keep it hidden and then unhide it when required, or, show a gif or image etc.

I wanted to develop a robust plugin, where with a simply jQuery call I can display the loading screen and tear it down when the task is completed.

Below is the code. It depends on Font awesome and jQuery:

/**
 * Raj: Used basic sources from here: http://jsfiddle.net/eys3d/741/
 **/


(function($){
    // Retain count concept: http://stackoverflow.com/a/2420247/260665
    // Callers should make sure that for every invocation of loadingSpinner method there has to be an equivalent invocation of removeLoadingSpinner
    var retainCount = 0;

    // http://stackoverflow.com/a/13992290/260665 difference between $.fn.extend and $.extend
    $.extend({
        loadingSpinner: function() {
            // add the overlay with loading image to the page
            var over = '
' +
                ''+
                '
';
            if (0===retainCount) {
                $(over).appendTo('body');
            }
            retainCount++;
        },
        removeLoadingSpinner: function() {
            retainCount--;
            if (retainCount<=0) {
                $('#custom-loading-overlay').remove();
                retainCount = 0;
            }
        }
    });
}(jQuery)); 

Just put the above in a js file and include it throughout the project.

CSS addition:

#custom-loading-overlay {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
    background: #000;
    opacity: 0.8;
    filter: alpha(opacity=80);
}
#custom-loading {
    width: 50px;
    height: 57px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -28px 0 0 -25px;
}

Invocation:

$.loadingSpinner();
$.removeLoadingSpinner();