slidetoggle without moving bottom content

by Akram kamal

HTML

<form>
    <div id="wrapper" style="width:400px">
        <div id="front" style="background-color: #DDDDDD">Lorem Ipsum
            <br />Lorem Ipsum
            <br />Lorem Ipsum
            <br />Lorem Ipsum
            <br />Lorem Ipsum
            <br />Lorem Ipsum
            <br />Lorem Ipsum
            <br />
        </div>
        <div id="back" style="background-color: yellow;">
            <select>
                <option>A</option>
                <option>B</option>
                <option>C</option>
            </select>
            <br />
            <select>
                <option>1</option>
                <option>2</option>
                <option>3</option>
            </select>
        </div>
    </div>
    <div id="closer" class="btn">up</div>
    <div id="opener" class="btn">down</div>
</form>

CSS

.btn {
    cursor: pointer;
    display: inline-block;
    background-color: #e6e6e6;
    background-repeat: no-repeat;
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#ffffff), color-stop(25%, #ffffff), to(#e6e6e6));
    background-image: -webkit-linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
    background-image: -moz-linear-gradient(top, #ffffff, #ffffff 25%, #e6e6e6);
    background-image: -ms-linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
    background-image: -o-linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
    background-image: linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#e6e6e6', GradientType=0);
    padding: 5px 14px 6px;
    text-shadow: 0 1px 1px rgba(255, 255, 255, 0.75);
    color: #333;
    font-size: 13px;
    line-height: normal;
    border: 1px solid #ccc;
    border-bottom-color: #bbb;
    -webkit-border-radius: 4px;
    -moz-border-radius: 4px;
    border-radius: 4px;
    -webkit-box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
    -moz-box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
    -webkit-transition: 0.1s linear all;
    -moz-transition: 0.1s linear all;
    -ms-transition: 0.1s linear all;
    -o-transition: 0.1s linear all;
    transition: 0.1s linear all;
}
#wrapper {
    overflow:hidden;
}

JavaScript

var pos = $("#front").position();
$("#back").hide();
$("#wrapper, #back").height($("#front").height());

$("#opener").click(function () {
    $("#front").stop().slideDown();
    $("#back").stop().slideUp();
})
$("#closer").click(function () {
    $("#front").stop().slideUp();
    $("#back").stop().slideDown();
});