JavaScript Tabs - Create Tabbed Web Pages Easily

Learn how to use JavaScript to create a tabbed Web page for holding lots of content. Full code included for copying and pasting into your website!

This tutorial shows how to create a Web page containing JavaScript-driven tabs. Each tab displays a separate chunk of content when clicked — perfect if your page needs to hold a large amount of content. It's also great for things such as multi-step ("wizard"-style) Web forms.

Click the link below to see a tabbed page in action:

The JavaScript and markup are coded in such a way that the page degrades gracefully in browsers that don't support JavaScript.

In this tutorial you learn how this tabbed page is put together. You can then use the code and ideas to build your own tabbed Web pages. Let's get started!

Creating the HTML for the tabbed page

The HTML for the tabs and content is very simple. You store each tab's content within a div element with a class of tabContent and a unique id for reference. Here's the first of the 3 tab content divs in the example:

<div class="tabContent" id="about">
  <h2>About JavaScript tabs</h2>
  <div>
    <p>JavaScript tabs partition your Web page content into tabbed sections. Only one section at a time is visible.</p>
    <p>The code is written in such a way that the page degrades gracefully in browsers that don't support JavaScript or CSS.</p>
  </div>
</div>

The tabs themselves are simply links within an unordered list:

<ul id="tabs">
  <li><a href="#about">About JavaScript tabs</a></li>
  <li><a href="#advantages">Advantages of tabs</a></li>
  <li><a href="#usage">Using tabs</a></li>
</ul>

Give the ul an id of "tabs" so that the JavaScript code can locate it. Each link within the list links to its corresponding content div by referencing the id of the div ("about", "advantages", or "usage"). Since these are standard HTML links, they work fine even without JavaScript.

You can add as many tabs as you like to the page. Simply add a new content div and give it a unique id, then add a link to it within the tabs list.

Creating the CSS

Some CSS is needed in order to make the tabs look like tabs (and make them nice to look at):

body { font-size: 80%; font-family: 'Lucida Grande', Verdana, Arial, Sans-Serif; }
ul#tabs { list-style-type: none; margin: 30px 0 0 0; padding: 0 0 0.3em 0; }
ul#tabs li { display: inline; }
ul#tabs li a { color: #42454a; background-color: #dedbde; border: 1px solid #c9c3ba; border-bottom: none; padding: 0.3em; text-decoration: none; }
ul#tabs li a:hover { background-color: #f1f0ee; }
ul#tabs li a.selected { color: #000; background-color: #f1f0ee; font-weight: bold; padding: 0.7em 0.3em 0.38em 0.3em; }
div.tabContent { border: 1px solid #c9c3ba; padding: 0.5em; background-color: #f1f0ee; }
div.tabContent.hide { display: none; }

These CSS rules work as follows:

body

This sets a nice font and font size for the page.

ul#tabs

Styles the tabs list, turning off bullet points.

ul#tabs li

The display: inline; property makes the tabs appear across the page.

ul#tabs li a

Styles the links within the list. Each link is given a border around every side except the bottom, so that the active tab blends nicely with its content div below.

ul#tabs li a:hover

Highlights a tab when hovered over with the mouse.

ul#tabs li a.selected

Styles a selected tab by giving it a lighter background and bold text, and making it bigger. Notice that the bottom padding is increased to 0.38em to make sure that the tab blends with the content div.

div.tabContent

Sets a style for the tab content areas so that they match the tab design.

div.tabContent.hide

Used to hide unselected tabs.

Creating the JavaScript code

Finally, of course, you need JavaScript to make the tabs work. Here's what the JavaScript needs to do:

• Attach a showTab() onclick event handler to each of the tab links.
• Hide all content divs except the first, so that only the leftmost tab's content is visible when the page loads.
• When a tab is clicked, showTab() displays the current tab content, and hides all other tab content divs. It also highlights the clicked tab and dims the other tabs.

The JavaScript kicks off by creating two arrays to hold the tab link elements and the content divs:

    var tabLinks = new Array();
    var contentDivs = new Array();

Four functions control the tabs:

• init() sets up the tabs.
• showTab() displays a clicked tab's content and highlights the tab.
• getFirstChildWithTagName() is a helper function that retrieves the first child of a given element that has a given tag name.
• getHash() is another short helper function that takes a URL and returns the part of the URL that appears after the hash (#) symbol.

Here's how these functions work.

The init() function

The first, and most complex, function is init(). It's called when the page loads, thanks to the body element's onload event:

  <body onload="init()">

Here's the function itself:

    function init() {

      // Grab the tab links and content divs from the page
      var tabListItems = document.getElementById('tabs').childNodes;
      for ( var i = 0; i < tabListItems.length; i++ ) {
        if ( tabListItems[i].nodeName == "LI" ) {
          var tabLink = getFirstChildWithTagName( tabListItems[i], 'A' );
          var id = getHash( tabLink.getAttribute('href') );
          tabLinks[id] = tabLink;
          contentDivs[id] = document.getElementById( id );
        }
      }

      // Assign onclick events to the tab links, and
      // highlight the first tab
      var i = 0;

      for ( var id in tabLinks ) {
        tabLinks[id].onclick = showTab;
        tabLinks[id].onfocus = function() { this.blur() };
        if ( i == 0 ) tabLinks[id].className = 'selected';
        i++;
      }

      // Hide all content divs except the first
      var i = 0;

      for ( var id in contentDivs ) {
        if ( i != 0 ) contentDivs[id].className = 'tabContent hide';
        i++;
      }
    }

This function does 3 things:

1. It loops through all the li elements in the tabs unordered list. For each li element, it calls the getFirstChildWithTagName() helper function to retrieve the a link element inside. Then it calls the getHash() helper function to extract the part of the link's URL after the hash; this is the ID of the corresponding content div. The link element is then stored by ID in the tabLinks array, and the content div is stored by ID in the contentDivs array.
2. It assigns an onclick event handler function called showTab() to each tab link, and highlights the first tab by setting its CSS class to 'selected'.
3. It hides all content divs except the first by setting each div's CSS class to 'tabContent hide'.

So that init() runs when the page loads, make sure you register it as the body element's onload event handler:

  <body onload="init()">

The showTab() function

showTab() is called whenever a tab link is clicked. It highlights the selected tab and shows the associated content div. It also dims all other tabs and hides all other content divs:

    function showTab() {
      var selectedId = getHash( this.getAttribute('href') );

      // Highlight the selected tab, and dim all others.
      // Also show the selected content div, and hide all others.
      for ( var id in contentDivs ) {
        if ( id == selectedId ) {
          tabLinks[id].className = 'selected';
          contentDivs[id].className = 'tabContent';
        } else {
          tabLinks[id].className = '';
          contentDivs[id].className = 'tabContent hide';
        }
      }

      // Stop the browser following the link
      return false;
    }

The function extracts the selected ID from the clicked link's href attribute and stores it in selectedId. It then loops through all the IDs. For the selected ID it highlights the corresponding tab and shows the content div; for all other IDs it dims the tab and hides the content div. It does all this by setting CSS classes on the tab links and content divs.

Finally the function returns false to prevent the browser from following the clicked link and adding the link to the browser history.

The getFirstChildWithTagName() function

This helper function returns the first child of a specified element that matches a specified tag name. init() calls this function to retrieve the a (link) element inside each list item in the tabs list.

    function getFirstChildWithTagName( element, tagName ) {
      for ( var i = 0; i < element.childNodes.length; i++ ) {
        if ( element.childNodes[i].nodeName == tagName ) return element.childNodes[i];
      }
    }

The function loops through the child nodes of element until it finds a node that matches tagName. It then returns the node.

Learn about the childNodes and nodeName properties in the article Looking inside DOM page elements.

The getHash() function

The getHash() helper function returns the portion of a URL after any hash symbol. Used by init() and showTab() to extract the content div ID referenced in a tab link.

    function getHash( url ) {
      var hashPos = url.lastIndexOf ( '#' );
      return url.substring( hashPos + 1 );
    }

Putting it together

That's all there is to creating JavaScript-enabled tabs! Take another look at the demo again, and view the page source to see how the HTML, CSS and JavaScript code appear in the page:

• The CSS and JavaScript go inside the page's head element. (You can move these into separate .css and .js files and link to them, if you prefer.)
• The page's body element contains the onload event handler to trigger the init() function.
• The tabs ul element contains the tab links.
• Each tab's content is stored in a div with a class of tabContent and a unique id (referenced in the corresponding tab link).

Feel free to use this code in your own Web pages. Happy tabbing!

Related articles

• A JavaScript Accordion to Show and Hide HTML
• Changing Page Elements with the DOM
• Looking Inside DOM Page Elements
• Retrieving Page Elements via the DOM
• Introducing the JavaScript DOM

Responses to this article

20 most recent responses (oldest first):

ul#tabs li a { color: #42454a; background-color: #dedbde; border: 1px solid #c9c3ba; border-bottom: none; padding: 0.3em 0.6em; text-decoration: none; }

div.tabContent { border: 1px solid #c9c3ba; padding: 0.5em; background-color: #f1f0ee; width:75%;}

div.tabContent { border: 1px solid #c9c3ba; padding: 0.5em; background-color: #f1f0ee; width:450px;}

You're welcome

<p><a onclick="return showTab(this)" href="#tab2">Go to the next tab</a>

View all 257 responses »

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