访问offsetParent时是否存在IE 6/7"未指定错误"错误的解决方法

@arilanto - 我在jquery脚本之后包含了这个脚本.性能方面,它不是最好的解决方案,但它是一个快速简单的解决方案.

function IESafeOffsetParent(elem)
{
    try
    {
       return elem.offsetParent;
    }
    catch(e)
    {        
      return document.body;
    }
}

// The Offset Method
// Originally By Brandon Aaron, part of the Dimension Plugin
// http://jquery.com/plugins/project/dimensions
jQuery.fn.offset = function() {
/// 

///     Gets the current offset of the first matched element relative to the viewport.
/// 
/// An object with two Integer properties, 'top' and 'left'.

var left = 0, top = 0, elem = this[0], results;

if ( elem ) with ( jQuery.browser ) {
    var parent     = elem.parentNode,
        offsetChild  = elem,
        offsetParent = IESafeOffsetParent(elem),
        doc       = elem.ownerDocument,
        safari2   = safari && parseInt(version) < 522 && !/adobeair/i.test(userAgent),
        css       = jQuery.curCSS,
        fixed       = css(elem, "position") == "fixed";

    // Use getBoundingClientRect if available
    if (false && elem.getBoundingClientRect) {
        var box = elem.getBoundingClientRect();

        // Add the document scroll offsets
        add(box.left + Math.max(doc.documentElement.scrollLeft, doc.body.scrollLeft),
            box.top  + Math.max(doc.documentElement.scrollTop,  doc.body.scrollTop));

        // IE adds the HTML element's border, by default it is medium which is 2px
        // IE 6 and 7 quirks mode the border width is overwritable by the following css html { border: 0; }
        // IE 7 standards mode, the border is always 2px
        // This border/offset is typically represented by the clientLeft and clientTop properties
        // However, in IE6 and 7 quirks mode the clientLeft and clientTop properties are not updated when overwriting it via CSS
        // Therefore this method will be off by 2px in IE while in quirksmode
        add( -doc.documentElement.clientLeft, -doc.documentElement.clientTop );

    // Otherwise loop through the offsetParents and parentNodes
    } else {

        // Initial element offsets
        add( elem.offsetLeft, elem.offsetTop );

        // Get parent offsets
        while ( offsetParent ) {
            // Add offsetParent offsets
            add( offsetParent.offsetLeft, offsetParent.offsetTop );

            // Mozilla and Safari > 2 does not include the border on offset parents
            // However Mozilla adds the border for table or table cells
            if ( mozilla && !/^t(able|d|h)$/i.test(offsetParent.tagName) || safari && !safari2 )
                border( offsetParent );

            // Add the document scroll offsets if position is fixed on any offsetParent
            if ( !fixed && css(offsetParent, "position") == "fixed" )
                fixed = true;

            // Set offsetChild to previous offsetParent unless it is the body element
            offsetChild  = /^body$/i.test(offsetParent.tagName) ? offsetChild : offsetParent;
            // Get next offsetParent
            offsetParent = offsetParent.offsetParent;
        }

        // Get parent scroll offsets
        while ( parent && parent.tagName && !/^body|html$/i.test(parent.tagName) ) {
            // Remove parent scroll UNLESS that parent is inline or a table to work around Opera inline/table scrollLeft/Top bug
            if ( !/^inline|table.*$/i.test(css(parent, "display")) )
                // Subtract parent scroll offsets
                add( -parent.scrollLeft, -parent.scrollTop );

            // Mozilla does not add the border for a parent that has overflow != visible
            if ( mozilla && css(parent, "overflow") != "visible" )
                border( parent );

            // Get next parent
            parent = parent.parentNode;
        }

        // Safari <= 2 doubles body offsets with a fixed position element/offsetParent or absolutely positioned offsetChild
        // Mozilla doubles body offsets with a non-absolutely positioned offsetChild
        if ( (safari2 && (fixed || css(offsetChild, "position") == "absolute")) ||
            (mozilla && css(offsetChild, "position") != "absolute") )
                add( -doc.body.offsetLeft, -doc.body.offsetTop );

        // Add the document scroll offsets if position is fixed
        if ( fixed )
            add(Math.max(doc.documentElement.scrollLeft, doc.body.scrollLeft),
                Math.max(doc.documentElement.scrollTop,  doc.body.scrollTop));
    }

    // Return an object with top and left properties
    results = { top: top, left: left };
}

function border(elem) {
    /// 

    ///     This method is internal.
    /// 
    /// 
    add( jQuery.curCSS(elem, "borderLeftWidth", true), jQuery.curCSS(elem, "borderTopWidth", true) );
}

function add(l, t) {
    /// 

    ///     This method is internal.
    /// 
    /// 
    left += parseInt(l, 10) || 0;
    top += parseInt(t, 10) || 0;
}

return results;
};