A simple straightforward sortable table in JavaScript

sortable.html

<style><!--
TABLE,P {padding:0.2em;}
TH {padding: 0.2em;border:1px solid green;}
TH.sorted_up {background-color:#CFC;}
TH.sorted_down {background-color:#FCC;}
TD {padding: 0.2em;border:1px solid blue;}
TD.n {text-align:right;}
//--></style>

<table id="sortable" cellspacing="0" cellpadding="2">
<tr><th>A</th><th>B</th><th>C</th></tr>
<tr><td>test</td><td class="n">1</td><td sortby="0">zero</td></tr>
<tr><td>a</td><td class="n">5</td><td sortby="10">ten</td></tr>
<tr><td>aaa</td><td class="n">3</td><td sortby="180">one hundred and eighty</td></tr>
<tr><td>x</td><td class="n">4</td><td sortby="400">four hundred</td></tr>
<tr><td>y</td><td class="n">5</td><td sortby="1">one</td></tr>
<tr><td>z</td><td class="n">2</td><td sortby="300">three hundred</td></tr>
<tr><td>test</td><td class="n">10</td><td sortby="20">twenty</td></tr>
</table>

<script><!--
function cellSortValue(x)
{
    var a=x.sortby_renderedvalue;        
    if(!a)
    {
        a=x.getAttribute("sortby");
        a=new Number(a).valueOf()||a;
        if(!a&&x.className=="n")a=new Number(x.textContent||x.innerText).valueOf();
		if(!a)a=x.textContent||x.innerText;
        x.sortby_renderedvalue=a;
    }
    return a;
}

function initSortTable(tableX)
{
    tableX.sortSequence=[];
    tableX.rows[0].onclick=function(event)
    {
        var th=event.target||event.srcElement;
        var x;
        var y;
        var d;
        for(y=0;y<this.cells.length;y++)
            if(this.cells[y]==th)
                x=y;
            else
                this.cells[y].className="";
        if(th.className=="sorted_up")
        {
            th.className="sorted_down";
            d=-1;
        }
        else
        {
            th.className="sorted_up";
            d=1;
        }
        var t=this.parentElement.rows;
        var z=[];
        for(y=1;y<t.length;y++)z[z.length]=t[y];
        z.sort(
            function(a,b)
            {
                var i=0;
                var aa=cellSortValue(a.cells[x]);
                var bb=cellSortValue(b.cells[x]);
                var dd=d;
                while(aa==bb&&i<tableX.sortSequence.length)
                {
                    aa=cellSortValue(a.cells[tableX.sortSequence[i].i]);
                    bb=cellSortValue(b.cells[tableX.sortSequence[i].i]);
                    dd=tableX.sortSequence[i].d;
                    i++;
                }
                return ((aa==bb)?0:((aa<bb)?-dd:dd));
            });
        for(y=0;y<z.length;y++) this.parentElement.appendChild(z[y]);
        delete z;
        tableX.sortSequence.unshift({i:x,d:d});//TODO: nix duplicates
    };
}

initSortTable(document.getElementById("sortable"));
//--></script>