var curtainStep = 5;
var curtainTimeout = 1;
var curtainBottom = 0;
var curtainHeight = 10;

function getH() {
    curtainHeight = document.getElementById("ddd").clientHeight;
}

function lShow() {
    if (curtainBottom < curtainHeight) {
        curtainBottom += curtainStep;
        var rect = 'rect(auto, auto, ' + curtainBottom + 'px, auto)';
        document.getElementById("ddd").style.clip = rect;
        setTimeout(lShow, curtainTimeout);
    }
}

function lHide() {
    curtainHeight = document.getElementById("ddd").clientHeight;
    if (curtainBottom > 0) {
        curtainBottom -= curtainStep;
        var rect = 'rect(auto, auto, ' + curtainBottom + 'px, auto)';
        document.getElementById("ddd").style.clip = rect;
        setTimeout(lHide, curtainTimeout);
    }
}

function lOut() {
    timer = window.setTimeout(lHide, 1500);
}

function lOn() {
    window.clearTimeout(timer);
}