function backcall(){
    var status = document.getElementById('backcallmsgdiv');
    status.style.height="500px";
    status.style.border = "1px solid #A52629";
    status.style.overflow = "visible";

}
function closebc(){
    var status = document.getElementById('backcallmsgdiv');
    status.style.height="0px";
    status.style.border = "0px solid #A52629";
    status.style.overflow = "hidden";
    status.addEventListener("click", stopEvent, false);

}


<div class="cl1"><a href="#" onclick="backcall()" >Свяжитесь с нами</a></div>
                <div id="backcallmsgdiv">
                    <a href="#" onclick="closebc()" ><div id="close">X</div></a>
                    <div class="tre"></div>
                </div>