size watcher v2

Triggering the scroll event by increasing wrapper size

by smnh

HTML

<div id="stage" class="preserve3d">


    <div id="contentShadow" class="preserve3d">
        <div class="bottomLayer preserve3d">
            <div class="bottomLayer">
                <div id="innerContentShadow">
                    <div id="innerScrollTopBrace" class="scrollTopBrace">
                      <div class="scrollTopLabelWrapper">
                        <div class="scrollTopLabel">
                          scrollTop: <span id="innerScrollTopValue"></span>
                        </div>
                      </div>
                    </div>
                    <div class="label">

                    </div>
                </div>
            </div>
            <div id="innerWrapper" class="wrapper"><div id="innerContent"></div></div>
            <div id="innerScrollLabel" class="scrollLabel">scrolled</div>
            <div class="label">inner wrapper</div>
        </div>
        <div id="decreaseHeightButton">&#9650; -40px</div>
        <div id="increaseHeightButton">&#9660; +40px</div>
        <div class="label">content</div>
    </div>
</div>

CSS

#stage {
    position:absolute;
    top:50px;
    left:300px;
    font-size: 20px;
    /* for browsers not supporting 3d transforms fallback to this */
    -webkit-transform: rotate(-30deg) skew(10deg);
    -moz-transform: rotate(-30deg) skew(10deg);
    -ms-transform: rotate(-30deg) skew(10deg);
    transform: rotate(-90deg) skew(30deg);
    /* for browsers supporting 3d transforms */
    -webkit-transform: rotateX(-45deg) rotateZ(-55deg);
    -moz-transform: rotateX(-45deg) rotateZ(-55deg);
    -ms-transform: rotateX(-45deg) rotateZ(-55deg);
    transform: rotateX(45deg) rotateZ( 35deg);
}
#contentShadow {
    position:absolute;
    width: 200px;
    height: 300px;
    background-color: #999999;
}
#decreaseHeightButton, #increaseHeightButton {
    position: absolute;
    left: -104px;
    width: 100px;
    height: 38px;
    line-height: 38px;
    text-align: center;
    border: 1px solid #999999;
    background-color: #cccccc;
    cursor: pointer;
}
#decreaseHeightButton {
    bottom: 1px;
}
#increaseHeightButton {
    bottom: -41px;
}
#innerContent {
    height: 400px;
}
#innerContentShadow {
    position: absolute;
    width: 100%;
    height: 400px;
    background-color: #cccccc;
}
.scrollTopBrace {
    position: absolute;
    top: 0;
    width: 10px;
    border: 2px solid #333333;
}
#innerScrollTopBrace {
    left: -15px;
    border-right-width: 0;
}
.scrollTopLabelWrapper {
    position: absolute;
    top: 50%;
}
.scrollTopLabel {
    position: absolute;
    white-space: nowrap;
}
#innerScrollTopBrace .scrollTopLabel {
    -webkit-transform: translate(-105%, -50%);
    -moz-transform: translate(-105%, -50%);
    -ms-transform: translate(-105%, -50%);
    transform: translate(-105%, -50%);
}
.wrapper {
    position: absolute;
    overflow: auto;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    box-shadow: 0 0 8px 4px #333333 inset;
    border: 2px solid #333333;
}
.label {
    position: absolute;
    right: 5px;
    bottom: 5px;
    /* chrome bug...

JavaScript

var decreaseHeightButton = document.getElementById("decreaseHeightButton"),
    increaseHeightButton = document.getElementById("increaseHeightButton"),
    contentShadow = document.getElementById("contentShadow"),
    innerWrapper = document.getElementById("innerWrapper"),
    innerScrollLabel = document.getElementById("innerScrollLabel"),
    innerContentShadow = document.getElementById("innerContentShadow"),
    innerScrollTopBrace = document.getElementById("innerScrollTopBrace"),
    innerScrollTopValue = document.getElementById("innerScrollTopValue"),
    innerScrollLabelHideTimeout = null;

function updateInnerScrollTop() {
    innerContentShadow.style.top = -innerWrapper.scrollTop + "px";
    innerScrollTopBrace.style.height = innerWrapper.scrollTop + "px";
    innerScrollTopValue.textContent = innerWrapper.scrollTop + "px";
}

function showInnerScrollLabel() {
    innerScrollLabel.className = "scrollLabel show";
    window.clearTimeout(innerScrollLabelHideTimeout);
    innerScrollLabelHideTimeout = window.setTimeout(hideInnerScrollLabel, 500);
}

function hideInnerScrollLabel(e) {
    innerScrollLabel.className = "scrollLabel hide";
    innerScrollLabelHideTimeout = null;
}

innerWrapper.scrollTop = innerWrapper.scrollHeight - innerWrapper.clientHeight;
updateInnerScrollTop();

decreaseHeightButton.addEventListener("click", function() {
    contentShadow.style.height = (contentShadow.offsetHeight - 40) + "px";
}, false);

increaseHeightButton.addEventListener("click", function () {
    contentShadow.style.height = (contentShadow.offsetHeight + 40) + "px";
    updateInnerScrollTop();
}, false);

innerWrapper.addEventListener("scroll", function() {
    updateInnerScrollTop();
    showInnerScrollLabel();
}, false);