如果你也想這么做，那么你還需要我的getElementByTagNames()函數。
代碼如下:
function createTOC() {
    var y = document.createElement('div');
    y.id = 'innertoc';
    var a = y.appendChild(document.createElement('span'));
    a.onclick = showhideTOC;
    a.id = 'contentheader';
    a.innerHTML = 'show page contents';
    var z = y.appendChild(document.createElement('div'));
    z.onclick = showhideTOC;
    var toBeTOCced = getElementsByTagNames('h2,h3,h4,h5');
    if (toBeTOCced.length < 2) return false;

    for (var i=0;i<toBeTOCced.length;i++) {
        var tmp = document.createElement('a');
        tmp.innerHTML = toBeTOCced[i].innerHTML;
        tmp.className = 'page';
        z.appendChild(tmp);
        if (toBeTOCced[i].nodeName == 'H4')
            tmp.className += ' indent';
        if (toBeTOCced[i].nodeName == 'H5')
            tmp.className += ' extraindent';
        var headerId = toBeTOCced[i].id || 'link' + i;
        tmp.href = '#' + headerId;
        toBeTOCced[i].id = headerId;
        if (toBeTOCced[i].nodeName == 'H2') {
            tmp.innerHTML = 'Top';
            tmp.href = '#top';
            toBeTOCced[i].id = 'top';
        }
    }
    return y;
}

var TOCstate = 'none';

function showhideTOC() {
    TOCstate = (TOCstate == 'none') ? 'block' : 'none';
    var newText = (TOCstate == 'none') ? 'show page contents' : 'hide page contents';
    document.getElementById('contentheader').innerHTML = newText;
    document.getElementById('innertoc').lastChild.style.display = TOCstate;
}

解釋
這段代碼運行如下：
準備階段
首先我創建一個<div id="innertoc">來放置表格內容
代碼如下:
function createTOC() {
var y = document.createElement('div');
y.id = 'innertoc';

然后在他的上面添加一個<span>標簽。點擊這個元素就會運行showhideTOC()函數，我會在下面解釋。