Question

I have a container div that need to be flexible in height because the content inside the div can change when users click on the button.

<div id="container">
        <div id="divBuyNow">
            <button id="btnBuyNow">
                Buy Now</button>
        </div>
</div>

$("#btnBuyNow").click(function () {

                $("#divBuyNow").animate({
                    opacity: 0,
                    marginRight: '200px'
                }, 1000, function () {
                    $("#divBuyNow").hide();
                });


                $("#platformsContainer").animate({
                    opacity: 1,
                    marginRight: '170px'
                }, 2000);
            });

Answer 1

What I understand is you want to animate platformContainer to height based on the content. If yes, set overflow:hidden to container and modify contents to innerDiv inside the container with opacity:0. When you want to show, get the height of innerDiv and animate container div to height + margins and other offset.