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jquery animation queue

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Part 44 - Optimise jQuery image gallery
Part 45 - jquery image slideshow with thumbnails
Part 46 - jquery animate function



In this video we will discuss how jQuery animation queues work.



When several calls to animate() method are chained together. By default these calls are placed into a queue to be executed one after the other in series rather than executing all of them simultaneously in parallel. The name of this queue is fx.

Each HTML element has its own queue. With the following code there will be 5 calls to animate method placed in the queue of each div element. This means both div elements (myDiv1 & myDiv2) may start to execute the first call to animate method more or less at the same time. However, from the given queue the queued methods are executed one after the other in series.

<html>
<head>
    <style>
        .myDivClass {
            width: 150px;
            padding: 5px;
            font-size: 18px;
            border: 1px solid black;
            opacity: .4;
            background-color: red;
            color: white;
        }
    </style>
    <script src="jquery-1.11.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $('#myButton').click(function () {
                $('#myDiv1')
                    .animate({ 'width': 500 }, 1500)
                    .animate({ 'padding': 20 }, 1500)
                    .animate({ 'font-size': 50 }, 1500)
                    .animate({ 'border-width': 10 }, 1500)
                    .animate({ 'opacity': 1 }, 1500);

                $('#myDiv2')
                    .animate({ 'width': 500 }, 1500)
                    .animate({ 'padding': 20 }, 1500)
                    .animate({ 'font-size': 50 }, 1500)
                    .animate({ 'border-width': 10 }, 1500)
                    .animate({ 'opacity': 1 }, 1500);
            });
        });
    </script>
</head>
<body style="font-family:Arial">
    <input type="button" id="myButton" value="Start Animation" />
    <br /><br />
    <div id="myDiv1" class="myDivClass">
        jQuery animations
    </div>
    <br />
    <div id="myDiv2" class="myDivClass">
        Pragim Tech
    </div>
</body>
</html>

The following code finds the total number of method calls waiting in the queue. While the first call to animate method is being executed, the other calls are added to the queue and waiting to be executed one after the other in sequence.

$('#myDiv1')
    .animate({ 'width': 500 }, 1500)
    .queue(function () {
        console.log('Queued calls = ' +
            $(this).queue('fx').length); $(this).dequeue();
    })
    .animate({ 'padding': 20 }, 1500)
    .animate({ 'font-size': 50 }, 1500)
    .animate({ 'border-width': 10 }, 1500)
    .animate({ 'opacity': 1 }, 1500)
    .queue(function () {
        console.log('Queued calls = ' +
            $(this).queue('fx').length); $(this).dequeue();
    });

To globally disable all animations
$.fx.off = true or jQuery.fx.off = true

The following example toggles animation on and off
<html>
<head>
    <style>
        .myDivClass {
            width: 150px;
            padding: 5px;
            font-size: 18px;
            border: 1px solid black;
            opacity: .4;
            background-color: red;
            color: white;
        }
    </style>
    <script src="jquery-1.11.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $('#myButton').click(function () {
                jQuery.fx.off = $('#chkBox').is(':checked');

                $('#myDiv1')
                    .animate({ 'width': 500 }, 1500)
                    .animate({ 'padding': 20 }, 1500)
                    .animate({ 'font-size': 50 }, 1500)
                    .animate({ 'border-width': 10 }, 1500)
                    .animate({ 'opacity': 1 }, 1500)

                $('#myDiv2')
                    .animate({ 'width': 500 }, 1500)
                    .animate({ 'padding': 20 }, 1500)
                    .animate({ 'font-size': 50 }, 1500)
                    .animate({ 'border-width': 10 }, 1500)
                    .animate({ 'opacity': 1 }, 1500);
            });
        });
    </script>
</head>
<body style="font-family:Arial">
    <input type="button" id="myButton" value="Start Animation" />
    <input id="chkBox" type="checkbox" /> Turn off animations
    <br /><br />
    <div id="myDiv1" class="myDivClass">
        jQuery animations
    </div>
    <br />
    <div id="myDiv2" class="myDivClass">
        Pragim Tech
    </div>
</body>
</html>

If you want the calls to animate() to be executed simultaneously in parallel, then set queue option to false. Modify the jQuery code as shown below.

$('#myDiv1')
    .animate({ 'width': 500 }, { duration: 1500, queue: false })
    .animate({ 'padding': 20 }, { duration: 1500, queue: false })
    .animate({ 'font-size': 50 }, { duration: 1500, queue: false })
    .animate({ 'border-width': 10 }, { duration: 1500, queue: false })
    .animate({ 'opacity': 1 }, { duration: 1500, queue: false });

$('#myDiv2')
    .animate({ 'width': 500 }, { duration: 1500, queue: false })
    .animate({ 'padding': 20 }, { duration: 1500, queue: false })
    .animate({ 'font-size': 50 }, { duration: 1500, queue: false })
    .animate({ 'border-width': 10 }, { duration: 1500, queue: false })
    .animate({ 'opacity': 1 }, { duration: 1500, queue: false });

There are 2 variations of animate method. We discussed Variation 1 in Part 46 of jQuery tutorial. In the code snippet above we are using Variation 2. 

Variation 1
.animate( properties [, duration ] [, easing ] [, complete ] )

Variation 2
.animate( properties, options )

For the list of all additional options that you can pass to animate method please check http://api.jquery.com/animate

An easier way to animate multiple css properties simultaneously in parallel, is to include all those css properties in a single JSON object.

$('#myDiv1')
    .animate({
        'width': 500,
        'padding': 20,
        'font-size': 50,
        'border-width': 10,
        'opacity': 1
    }, 1500);

$('#myDiv2')
    .animate({
        'width': 500,
        'padding': 20,
        'font-size': 50,
        'border-width': 10,
        'opacity': 1
    }, 1500);

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