javascript YUI code reading diary YAHOO.util.Dom - Part.4_YUI.Ext related

var getXY = function() {
// Determine whether it is IE
if (document.documentElement.getBoundingClientRect) {
// Note 1
return function(el) {
var box = el.getBoundingClientRect();

var rootNode = el.ownerDocument; 🎜> Y.Dom.getDocumentScrollTop (rootNode)];
                                                  parentNode = el.offsetParent ; > // Determine whether the node is absolute under Safari,
// Whether the parent element is body
// Note 2.
var accountforBody = > Y.Dom.getStyle(el, 'position') == 'absolute' &&
el.offsetParent == el.ownerDocument.body);

// If the parent element Not itself
if (parentNode != el) {
                                                                                                                                                                                                    ; .offsettop;
y.DOM.GetStyle (Parentnode, 'Position')
== 'Absolute') {
AccountForbody = True;
}
Parentnod e = Parentnode.OffsetParent;
}
         }

            //　还是针对 Safari 的
            if (accountForBody) { //safari doubles in this case
                pos[0] -= el.ownerDocument.body.offsetLeft;
                pos[1] -= el.ownerDocument.body.offsetTop;
            } 
            parentNode = el.parentNode;

            // account for any scrolled ancestors
            while ( parentNode.tagName && 
                         !patterns.ROOT_TAG.test(parentNode.tagName) ) 
            {
               // work around opera inline/table scrollLeft/Top bug
               // 注3.
               if (Y.Dom.getStyle(parentNode, 'display')
                                  .search(/^inline|table-row.*$/i)) { 
                    pos[0] -= parentNode.scrollLeft;
                    pos[1] -= parentNode.scrollTop;
                }

                parentNode = parentNode.parentNode; 
            }

            return pos;
        };
    }
}() // NOTE: Executing for loadtime branching注. 有关 IE 的 getBoundingClientRect 方法，可以参考这里。
注. Safari 的 BUG，详细情况参见这里。
注. 参见老外的原话（出处）：
"- Remove parent scroll UNLESS that parent is inline or a table 
to work around Opera inline/table scrollLeft/Top bug"
Fixed in Opera 9.5. (also, Opera 9.5 supports getBoundingClientRect 
and getClientRects.)最后，有关更多 DOM 的兼容性，可以参看 PPK 的总结（怎么又是他）。