Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script> 
$(document).ready(function(){
    function aniDiv(){
        $("div:eq(0)").animate({width: "50%"}, "slow");
        $("div:eq(0)").animate({width: "100%"}, "slow", aniDiv);
    }
    aniDiv();
    $(".btn1").click(function(){
        $(":animated").css("background-color", "red");
    });
});
</script>
</head>
<body>

<button class="btn1">Change color of the animated element</button>

<div style="background:blue;">Div 1</div>
<div style="background:green;">Div 2</div>
<div style="background:yellow;">Div 3</div>

</body>
</html>