实例如下所示：
获取滚动条距离顶部位置
function getScrollTop() {
var scrollTop = 0;
if (document.documentElement && document.documentElement.scrollTop) {
scrollTop = document.documentElement.scrollTop;
} else if (document.body) {
scrollTop = document.body.scrollTop;
}
return scrollTop;
}
//获取当前可视范围的高度
function getClientHeight() {
var clientHeight = 0;
if (document.body.clientHeight && document.documentElement.clientHeight) {
clientHeight = Math.min(document.body.clientHeight,document.documentElement.clientHeight);
} else {
clientHeight = Math.max(document.body.clientHeight,document.documentElement.clientHeight);
}
return clientHeight;
}
//获取文档完整的高度
function getScrollHeight() {
return Math.max(document.body.scrollHeight,document.documentElement.scrollHeight);
}
//判断滚动条是否达到底部
getScrollTop() + getClientHeight() == getScrollHeight()