1 //取窗口滚动条高度
2 function getScrollTop() {
3 var scrollTop = 0;
4 if (document.documentElement && document.documentElement.scrollTop) {
5 scrollTop = document.documentElement.scrollTop;
6 }
7 else if (document.body) {
8 scrollTop = document.body.scrollTop;
9 }
10 return scrollTop;
11 }
12
13
14 // 取窗口可视范围的高度
15 function getClientHeight() {
16 var clientHeight = 0;
17 if (document.body.clientHeight && document.documentElement.clientHeight) {
18 var clientHeight = (document.body.clientHeight < document.documentElement.clientHeight) ? document.body.clientHeight : document.documentElement.clientHeight;
19 }
20 else {
21 var clientHeight = (document.body.clientHeight > document.documentElement.clientHeight) ? document.body.clientHeight : document.documentElement.clientHeight;
22 }
23 return clientHeight;
24 }
25
26 // 取文档内容实际高度
27 function getScrollHeight() {
28 return Math.max(document.body.scrollHeight, document.documentElement.scrollHeight);
29 }
2 function getScrollTop() {
3 var scrollTop = 0;
4 if (document.documentElement && document.documentElement.scrollTop) {
5 scrollTop = document.documentElement.scrollTop;
6 }
7 else if (document.body) {
8 scrollTop = document.body.scrollTop;
9 }
10 return scrollTop;
11 }
12
13
14 // 取窗口可视范围的高度
15 function getClientHeight() {
16 var clientHeight = 0;
17 if (document.body.clientHeight && document.documentElement.clientHeight) {
18 var clientHeight = (document.body.clientHeight < document.documentElement.clientHeight) ? document.body.clientHeight : document.documentElement.clientHeight;
19 }
20 else {
21 var clientHeight = (document.body.clientHeight > document.documentElement.clientHeight) ? document.body.clientHeight : document.documentElement.clientHeight;
22 }
23 return clientHeight;
24 }
25
26 // 取文档内容实际高度
27 function getScrollHeight() {
28 return Math.max(document.body.scrollHeight, document.documentElement.scrollHeight);
29 }
滚动条到达底部的条件:getScrollTop() + getClientHeight() == getScrollHeight()