Mefi Navigator fixes

// ==UserScript==
// @name          MeFi Navigator
// @namespace     http://www.metafilter.com/
// @description   Navigate users' comments in Metafilter threads.
// @include       http://*.metafilter.com/*
// @include       http://metafilter.com/*
// @include       https://*.metafilter.com/*
// @include       https://metafilter.com/*
// @grant         none
// ==/UserScript==
if (/.*metafilter\.com\/(\d{1,7}\/|mefi\/|comments\.mefi).*/.test(window.location)) {
    var mfn_poster;
    var mfn_all = [];
    var mfn_div = document.createElement("div");
    mfn_preload();
    mfn_main(); // don't wait for page load event
}
function mfn_preload() {
    mfn_you = mfn_user();
    var css = document.createElement("style");
    css.setAttribute("type","text/css");
    css.innerHTML = "#mfn-dot { padding:0 2px 0 2px;font-size:9pt;line-height:0; } #mfn-arrow { padding:0 2px 0 2px;font-size:10pt;line-height:0;} #mfn-list{padding:0 2px 0 2px;font-size:9pt;line-height:0;} #navigator-list a { -moz-opacity:0.9;background:#666;font-size:8pt;font-family:Arial,sans-serif;border:1px solid #CCC;border-top:none;margin:0;display:block;padding:1px 3px 1px 3px;text-align:center; } #navigator-list li { border:0;margin:0;padding:0;} #navigator-list a:hover { -moz-opacity:1;}";
    document.getElementsByTagName("head")[0].appendChild(css);
    document.body.addEventListener("click",function() { mfn_div.innerHTML = "";mfn_div.style.display = "none"; },true);
    mfn_div.setAttribute("id","navigator-list");
    mfn_div.setAttribute("style","display:none;position:absolute;left:0;top:0;padding:1px 0 0 0;");
    document.body.appendChild(mfn_div);
    mfn_posterNode = document.createElement("span");
    mfn_posterNode.innerHTML = " poster ";
    mfn_posterNode.setAttribute("style","background:#D0D000;color:#222;margin:0 .5ex;");
    mfn_posterNode.setAttribute("class","staff");
    mfn_adminNode = mfn_posterNode.cloneNode(true);
    mfn_adminNode.innerHTML = "Admin";
    mfn_adminNode.style.background = "white";
    mfn_userNode = mfn_adminNode.cloneNode(true);
    mfn_userNode.innerHTML = " me ";
    mfn_userNode.setAttribute("style","background:#CC9;color:#333;margin:0 .5ex;");
    mfn_userNode.setAttribute("class","staff");
    mfn_zeroNode = document.createTextNode("No other comments.");
    var htmlDot = "<b id=\"mfn-dot\">&middot;</b>";
    var htmlLeft = "<a href=\"javascript:void(0);\" target='_self' id='mfn-arrow'>&laquo;</a>";
    var htmlList = "<a href=\"javascript:void(0)\" target='_self' id='mfn-list' onfocus='blur();'>&equiv;</a>";
    var htmlRight = "<a href=\"javascript:void(0);\" target='_self' id='mfn-arrow'>&raquo;</a>";
    mfn_htmlFirst = htmlDot + htmlList + htmlRight;
    mfn_htmlNormal = htmlLeft + htmlList + htmlRight;
    mfn_htmlLast = htmlLeft + htmlList + htmlDot;
}
function mfn_user() {
    var cookie = document.cookie.toString();
    var i = cookie.indexOf("USER_NAME");
    if (i == -1) {
        return false;
    } else {
        var j = cookie.indexOf(';',i);
        if (j == -1) j=cookie.length;
        return unescape(cookie.substring(i+10,j));
    }
}
function findPos(obj) {
    var curleft = 0;
    var curtop = 0;
    if(obj.offsetLeft) curleft += parseInt(obj.offsetLeft);
    if(obj.offsetTop) curtop += parseInt(obj.offsetTop);
    if(obj.scrollTop && obj.scrollTop > 0) curtop -= parseInt(obj.scrollTop);
    if(obj.offsetParent) {
        var pos = findPos(obj.offsetParent);
        curleft += pos[0];
        curtop += pos[1];
    } else if(obj.ownerDocument) {
        var thewindow = obj.ownerDocument.defaultView;
        if(!thewindow && obj.ownerDocument.parentWindow)
            thewindow = obj.ownerDocument.parentWindow;
        if(thewindow) {
            if(thewindow.frameElement) {
                var pos = findPos(thewindow.frameElement);
                curleft += pos[0];
                curtop += pos[1];
            }
        }
    }

    return [curleft,curtop];
}
function mfn_main() {
    var elements = document.evaluate('//div[@class="comments" or @class="copy" or @class="comments bestleft"]/span[@class="smallcopy" or @class="smallcopy postbyline"]',document.body,null,XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,null);
    mfn_poster = elements.snapshotItem(0).getElementsByTagName('a').item(0).textContent.toString();
    for (var i=0,element;element = elements.snapshotItem(i);i++) {
        var author = element.getElementsByTagName('a').item(0).textContent.toString();
        if (typeof(mfn_all[author]) == "object") { // 'splice' problem
            mfn_all[author].push(element);
        } else{
            mfn_all[author] = [element,];
        }
    }
    for (var author in mfn_all) {
        for (var i = 0,lim=mfn_all[author].length;i<lim;i++) {
            if (mfn_you != false && author == mfn_you) {
                mfn_all[author][i].getElementsByTagName('a').item(0).appendChild(mfn_userNode.cloneNode(true));
            }
            if (author == mfn_poster && i > 0) {
                mfn_all[author][i].getElementsByTagName('a').item(0).appendChild(mfn_posterNode.cloneNode(true));
            }
            if (lim==1) {
                mfn_all[author][i].appendChild(mfn_zeroNode.cloneNode(false));
            } else {
                var panel = document.createElement("span");
                var buffer = ["Other&nbsp;<small style='line-height:0;'>[",];
                buffer.push((i+1),"/",lim,"]</small>:&nbsp;");
                if (i==0) {
                    buffer.push(mfn_htmlFirst);
                } else if (i==(lim-1)) {
                    buffer.push(mfn_htmlLast);
                } else {
                    buffer.push(mfn_htmlNormal);
                }
                panel.innerHTML = buffer.join("");
                if (i > 0) panel.childNodes.item(3).addEventListener("click",function() {mfn_prev(this.parentNode);},true);
                panel.childNodes.item(4).addEventListener("click",function() {mfn_list(this.parentNode);},true);
                if (i < (lim-1)) panel.childNodes.item(5).addEventListener("click",function() {mfn_next(this.parentNode);},true);
                mfn_all[author][i].appendChild(panel);
            }
        }
    }
}
mfn_prev = function (panel) {
    var author = panel.parentNode.getElementsByTagName('a').item(0).childNodes.item(0).textContent;
    var i = panel.textContent.substring(panel.textContent.indexOf("[")+1,panel.textContent.indexOf("/"));
    if (author == mfn_poster && (i-2)==0) {
        window.location = "#top";
    } else {
        var link = mfn_all[author][i-2].getElementsByTagName('a').item(1).href;
        if (link.indexOf("faq.metafilter.com") !== -1) { //staff have an extra anchor element to the faq, we don't want that one
            link = mfn_all[author][i-2].getElementsByTagName('a').item(2).href;
        }
        window.location = link.substring(link.lastIndexOf("#"));
    }
};
mfn_list = function (icon) {
    var author = icon.parentNode.parentNode.getElementsByTagName('a').item(0).childNodes.item(0).textContent;
    var j = icon.parentNode.textContent.substring(icon.parentNode.textContent.indexOf("[")+1,icon.parentNode.textContent.indexOf("/"))*1;
    var buffer = [];
    if (author == mfn_poster) {
        var link = "#top";
    } else {
        var link = mfn_all[author][0].getElementsByTagName('a').item(1).href;
        link = link.substring(link.lastIndexOf("#"));
    }
    buffer.push("<a href='"+link+"' target='_self' style='float:left;font-size:8px;border-right:none;background:#111;' title='first'>&middot;&lt;</a>");
    link = mfn_all[author][mfn_all[author].length-1].getElementsByTagName('a').item(1).href;
    link = link.substring(link.lastIndexOf("#"));
    buffer.push("<a href='"+link+"' target='_self' style='float:left;font-size:8px;background:#111' title='last'>&gt;&middot;</a>");
    buffer.push("<div id='navigator-scroll' style='clear:both;height:200px;overflow:auto;'>");
    for (var i=0,lim=mfn_all[author].length;i<lim;i++) {
        if (author == mfn_poster && i==0) {
            link = "#top";
        } else {
            link = mfn_all[author][i].getElementsByTagName('a').item(1).href;
            if (link.indexOf("faq.metafilter.com") !== -1) {
                link = mfn_all[author][i].getElementsByTagName('a').item(2).href;
            }
            link = link.substring(link.lastIndexOf("#"));
        }
        buffer.push("<a href='"+link+"' target='_self' style='background:#"+(i%2==0?'444':'111')+((i+1)==j?';text-decoration:underline;color:white;':';')+"'>"+(i+1)+"</a>");
    }
    buffer.push("</div>");
    mfn_div.innerHTML = buffer.join("");
    icon_pos = findPos(icon);
    var new_left = icon_pos[0] + document.body.scrollLeft + "px";
    var new_top = icon_pos[1] + document.body.scrollTop + 20 + "px";
    mfn_div.setAttribute("style","display:block;position:absolute;left:"+(new_left)+";top:"+(new_top)+";padding:1px 0 0 0;");
};
mfn_next = function (panel) {
    var author = panel.parentNode.getElementsByTagName('a').item(0).childNodes.item(0).textContent;
    var i = panel.textContent.substring(panel.textContent.indexOf("[")+1,panel.textContent.indexOf("/"));
    var link = mfn_all[author][i].getElementsByTagName('a').item(1).href;
    if (link.indexOf("faq.metafilter.com") !== -1) { //staff have an extra anchor element to the faq, we don't want that one
        link = mfn_all[author][i].getElementsByTagName('a').item(2).href;
    }
    window.location = link.substring(link.lastIndexOf("#"));
};