Is there a JavaScript solution to generating a "table of contents" for a page?

I've modified the function in AtesGoral's accepted answer to output correctly nested lists and valid HTML5.

Just add the code below to your scripts and call TableOfContents(container, output); on load, where container is the class or id of your content element and output is the class or id of the TOC element. Default values are '#contents' and '#toc', respectively.

See http://codepen.io/aufmkolk/pen/RWKLzr for a working demo.

function TableOfContents(container, output) {
var toc = "";
var level = 0;
var container = document.querySelector(container) || document.querySelector('#contents');
var output = output || '#toc';

container.innerHTML =
    container.innerHTML.replace(
        /<h([\d])>([^<]+)<\/h([\d])>/gi,
        function (str, openLevel, titleText, closeLevel) {
            if (openLevel != closeLevel) {
                return str;
            }

            if (openLevel > level) {
                toc += (new Array(openLevel - level + 1)).join('<ul>');
            } else if (openLevel < level) {
                toc += (new Array(level - openLevel + 1)).join('</li></ul>');
            } else {
                toc += (new Array(level+ 1)).join('</li>');
            }

            level = parseInt(openLevel);

            var anchor = titleText.replace(/ /g, "_");
            toc += '<li><a href="#' + anchor + '">' + titleText
                + '</a>';

            return '<h' + openLevel + '><a href="#' + anchor + '" id="' + anchor + '">'
                + titleText + '</a></h' + closeLevel + '>';
        }
    );

if (level) {
    toc += (new Array(level + 1)).join('</ul>');
}
document.querySelector(output).innerHTML += toc;
};

JQuery comes to mind as a fast and easy solution. A quick google search for jquery table of contents yields two promising results:

  • jqTOC
  • Article on how to do this manually

I couldn't resist putting together a quick implementation.

Add the following script anywhere on your page:

window.onload = function () {
    var toc = "";
    var level = 0;

    document.getElementById("contents").innerHTML =
        document.getElementById("contents").innerHTML.replace(
            /<h([\d])>([^<]+)<\/h([\d])>/gi,
            function (str, openLevel, titleText, closeLevel) {
                if (openLevel != closeLevel) {
                    return str;
                }

                if (openLevel > level) {
                    toc += (new Array(openLevel - level + 1)).join("<ul>");
                } else if (openLevel < level) {
                    toc += (new Array(level - openLevel + 1)).join("</ul>");
                }

                level = parseInt(openLevel);

                var anchor = titleText.replace(/ /g, "_");
                toc += "<li><a href=\"#" + anchor + "\">" + titleText
                    + "</a></li>";

                return "<h" + openLevel + "><a name=\"" + anchor + "\">"
                    + titleText + "</a></h" + closeLevel + ">";
            }
        );

    if (level) {
        toc += (new Array(level + 1)).join("</ul>");
    }

    document.getElementById("toc").innerHTML += toc;
};

Your page should be structured something like this:

<body>
    <div id="toc">
        <h3>Table of Contents</h3>
    </div>
    <hr/>
    <div id="contents">
        <h1>Fruits</h1>
        <h2>Red Fruits</h2>
        <h3>Apple</h3>
        <h3>Raspberry</h3>
        <h2>Orange Fruits</h2>
        <h3>Orange</h3>
        <h3>Tangerine</h3>
        <h1>Vegetables</h1>
        <h2>Vegetables Which Are Actually Fruits</h2>
        <h3>Tomato</h3>
        <h3>Eggplant</h3>
    </div>
</body>

You can see it in action at https://codepen.io/scheinercc/pen/KEowRK (old link: http://magnetiq.com/exports/toc.htm (Works in IE, FF, Safari, Opera))


Here's a great script to do this:

https://github.com/matthewkastor/html-table-of-contents/wiki

To use it:

  1. Add this tag:

    <script src="./node_modules/html-table-of-contents/src/html-table-of-contents.js" type="text/javascript">

  2. Call the function, such as in your body's onload attribute:

    <body onload="htmlTableOfContents();">

Here is the definition of the method that does the generation:

/**
 * Generates a table of contents for your document based on the headings
 *  present. Anchors are injected into the document and the
 *  entries in the table of contents are linked to them. The table of
 *  contents will be generated inside of the first element with the id `toc`.
 * @param {HTMLDOMDocument} documentRef Optional A reference to the document
 *  object. Defaults to `document`.
 * @author Matthew Christopher Kastor-Inare III
 * @version 20130726
 * @example
 * // call this after the page has loaded
 * htmlTableOfContents();
 */
function htmlTableOfContents (documentRef) {
    var documentRef = documentRef || document;
    var toc = documentRef.getElementById('toc');
    var headings = [].slice.call(documentRef.body.querySelectorAll('h1, h2, h3, h4, h5, h6'));
    headings.forEach(function (heading, index) {
        var anchor = documentRef.createElement('a');
        anchor.setAttribute('name', 'toc' + index);
        anchor.setAttribute('id', 'toc' + index);

        var link = documentRef.createElement('a');
        link.setAttribute('href', '#toc' + index);
        link.textContent = heading.textContent;

        var div = documentRef.createElement('div');
        div.setAttribute('class', heading.tagName.toLowerCase());

        div.appendChild(link);
        toc.appendChild(div);
        heading.parentNode.insertBefore(anchor, heading);
    });
}

try {
     module.exports = htmlTableOfContents;
} catch (e) {
    // module.exports is not defined
}

Tags:

Javascript

Recent Posts