仿微博滚动条接近底部时加载

//整个网页滚动时
webPage.addEvent(window, "scroll", function () {
var rb = webPage.rightBottom();//当前页面区域右下角距网页左上角的位置差，见上一篇
if (rb.y + 50 >= webPage.size().height) {
document.body.appendChild(webPage.$div({ "width": 180, "height": 100, "color": "#970568", "x": 10, "y": 10, "z": 999, "styleText": "border:1px solid" }));
}
});

//某个div内
var tObj=document.getElementById("t");
webPage.addEvent(tObj, "scroll", function () {
var r = parseInt(tObj.scrollTop) + parseInt(tObj.style.height);
if (r + 20 >= tObj.scrollHeight) {
tObj.appendChild(webPage.$div({ "width": 10, "height": 10, "x": 10, "y": 10, "z": 999, styleText: "border:1px solid" }));
}
});