CSS/jquery animation on click

HTML

<div id="collapseTwo" class="cross">
                                <div class="panel-body">
                                    <div class="inner rotate">
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                        <div>     Hassan NAseer Ahmad
                                   </div>
                                  
                                    </div>
                                </div>
                            </div>

CSS

img {
    display: block;
margin: 20px;
}

img {
-webkit-transition-duration: 1s;
    -moz-transition-duration: 1s;
    -o-transition-duration: 1s;
    transition-duration: 1s;
    -webkit-transition-property: -webkit-transform;
    -moz-transition-property: -moz-transform;
    -o-transition-property: -o-transform;
    transition-property: transform;
}

JavaScript

$( ".cross" ).click(function() {
    //alert($( this ).css( "transform" ));
    if (  $( this ).css( "transform" ) == 'none' ){
        $(this).css("transform","rotate(90deg)");
    } else {
        $(this).css("transform","" );
    }
});