1 //get element size
2
3 function getElementLeft(element) {
4 var actualLeft = element.offsetLeft;
5 var current = element.offsetParent;
6
7 while (current !== null) {
8 actualLeft += current.offsetLeft;
9 current = current.offsetParent;
10 }
11
12 return actualLeft;
13 }
14
15 function getElementTop(element) {
16 var actualTop = element.offsetTop;
17 var current = element.offsetParent;
18
19 while (current !== null) {
20 actualTop += current.offsetTop;
21 current = current.offsetParent;
22 }
23
24 return actualTop;
25 }
26
27 function getViewport() {
28 if (document.compatMode == "BackCompat") {
29 return {
30 width: document.body.clientWidth,
31 height: document.body.clientHeight
32 };
33 } else {
34 return {
35 width: document.documentElement.clientWidth,
36 height:document.documentElement.clientHeight
37 };
38 }
39 }
40
41 function getBoundingClientRect(element) {
42 var scrollTop = document.documentElement.scrollTop;
43 var scrollLeft = document.documentElement.scrollLeft;
44
45 if (element.getBoundingClientRect) {
46 if (typeof arguments.callee.offset != "number") {
47 var temp = document.createElement("div");
48 temp.style.cssText = "position:absolute;left:0;top:0;";
49 document.body.appendChild(temp);
50 arguments.callee.offset = -temp.getBoundingClientRect().top - scrollTop;
51 document.body.removeChild(temp);
52 temp = null;
53 }
54
55 var rect = element.getBoundingClientRect();
56 var offset = arguments.callee.offset;
57
58 return {
59 left: rect.left + offset,
60 right: rect.right + offset,
61 top: rect.top + offset,
62 bottom: rect.bottom + offset
63 };
64 } else {
65
66 var actualLeft = getElementLeft(element);
67 var actualTop = getElementTop(element);
68
69 return {
70 left: actualLeft - scrollLeft,
71 right: actualLeft + element.offsetWidth - scrollLeft,
72 top: actualTop - scrollTop,
73 bottom:actualTop+element.offsetHeight-scrollTop
74 };
75 }
76 }
