prototype wrapper for YUI Dom utilities

http://chunghe.googlepages.com/prototype.wrapper.for.YUI.Dom.utilit.htm
用prototype把常用的一些 YUI Dom utilities (getRegion, getXY, getViewportHeight/getViewportWidth, getDocumentScrollTop/getDocumentScrollLeft)重寫一次，還是比較習慣YUI的naming convention，順便熟悉一下在prototype的哪些function mapping到YUI的哪些function。
值得一提的是 document.viewport.getDimensions().width;這個會把viewport width多算’17px’，之前在lightbox.js也有遇到一樣的問題，不是很確定，所以用了YUI的code把這部分補起來。另外YUI在IE底下，getXY在X與Y都多算了’2px’，prototype算起來倒是正確的。

var PUD = {    getXY: function(ele){        var ele = $(ele);        var pos = ele.positionedOffset();        return [pos.left, pos.top];    },

    getRegion: function(ele){        var ele = $(ele);        var pos = ele.positionedOffset();        var t   = pos[1];         var r   = pos[0] + ele.offsetWidth;        var b   = pos[1] + ele.offsetHeight;        var l   = pos[0];        return [t, r, b, l];    },

    getViewportHeight: function(ele){        return document.viewport.getDimensions().height;    },

    getWrongViewportWidth : function(ele){        // belowing method provided by prototype has '17px' margin error        return document.viewport.getDimensions().width;    },

    getViewportWidth : function(ele){        // belowing method provided by prototype has '17px' margin error        //return document.viewport.getDimensions().width;        var width = self.innerWidth;        var mode  = document.compatMode;

        if (mode || Prototype.Browser.IE) { // IE, Gecko, Opera            width = (mode == 'CSS1Compat') ?            document.documentElement.clientWidth : // Standards            document.body.clientWidth; // Quirks        }        return width;    },

    getDocumentScrollLeft : function(ele){        return document.viewport.getScrollOffsets()[0];    },

    getDocumentScrollTop : function(ele){        return document.viewport.getScrollOffsets()[1];    }}