June, 02 2004

May the fleas of a thousand camels swim to your rescue when you next fall from an ocean cruise-liner.

I have been putting together a static HTML site that has some long pages. It was becoming difficult to find content on some of these pages so I added an automagically generated table of contents.

The table of contents is generated from all H1, H2 and H3 headings on the page, except if there is only one heading, in which case the whole table of contents is removed.

My script is based on this article from quirksmode.org.

Here is the script:

// pageToc.js

//

// Ensure all H1, H2 and H3 headings are added to the page table of contents

//



window.onload = createTOC;



function createTOC()

{

  // find the nodes to be added to the Page TOC

  var tocTargets = new Array()

  nodes = document.getElementById('contentArea').childNodes

  for (var i = 0; i < nodes.length; i++) {

    nn = nodes[i].nodeName

    if (nn == "H1" || nn == "H2" || nn == "H3") {

      tocTargets.push(nodes[i])

    }

  }



  tocDiv = document.getElementById('pageToc')



  // Remove toc if none or one heading

  if (tocTargets.length <= 1) {

    tocDiv.parentNode.removeChild(tocDiv)

    return;

  }



  // Add the toc contents

  tocDiv = document.getElementById('pageToc')

  tocDiv.innerHTML= "<h2>Page Contents </h2>"

  tocList = document.createElement('ul')

  tocList.className = "pageToc"

  tocDiv.appendChild(tocList)

  // Insert elements into our table of contents

  for (var i = 0; i < tocTargets.length; i++) {

    tocTarget = tocTargets[i]

    if (tocTarget.id == '') {

      tocTarget.id = 'pageToc' + i

    }

    newItem = document.createElement('li')

    newItem.className = "pageToc" + tocTarget.nodeName

    newLink = document.createElement('a')

    newLink.href = '#' + tocTarget.id

    newLink.innerHTML = tocTarget.innerHTML

    newItem.appendChild(newLink)

    tocList.appendChild(newItem)

  }  

}

To use it, you need to add a reference to the script in each page header

<script src="/idsproj/theme/pageToc.js"></script>

This DIV element also needs to be added near the top of the body:

<div id="pageToc">

</div>

The script has been tested on Mozilla, Firefox and IE6. Feel free to use as you will, though I would appreciate a comment here if you do.