Making Scrollable Tables with fixed headers

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Although it is a common requirement, it’s not always straight forward to make scrollable tables with fixed headers. Here, we are going to try a few JavaScript solutions that could be suitable for most cases. I need to emphasize on that, because you might need to make a few tweaks to make it work in your environment, especially tables generated by web  frameworks.

Implementation

To implement these JavaScript solutions, your tables should have an ID and width. Width can be a fixed value or a percentage. Since the width can be specified in percentage, it should also work when window get resized. It has been designed to introduce this functionality with minimal changes to your existing pages. So for the JavaScript functions to work, you only need to add the following lines to your HTML pages,

<script type="text/javascript" src="fxheader1.js"></script>
<script type="text/javascript">
fxheaderInit('dataTable',300);
</script>

Make sure you add the second JavaScript call after the table element. Replace dataTable with the ID of your table, and 300 with the height you require. Instead of specifying the height as a fixed value, there are ways to stretch the table to fill the page based on other components on the page. Last solution make use of such a method.

Browser compatibility

It’s been tested on the following browsers all running on Windows XP.

• IE6
• IE7
• IE8
• Firefox 2.0
• Firefox 3.5
• Google Chrome

The big table

Here is an example of a table we are going to introduce the scrolling functionality. Well, it is not really big, just big enough to test our functionality 🙂

http://jaimonblog.appspot.com/datascroller/bigTable.html

Solution 1: Simple CSS only scrolling without fixing headers

With the help of a bit of CSS, we can implement a simple scroller. Enclose the table element within a div container with an overflow value of auto and a fixed height. Something like

<div style=’overflow:auto;height:300px;’>
<table …. />
</div>

You can see the demo at http://jaimonblog.appspot.com/datascroller/simpleScroller.html

Solution 2: Scrolling with fixed headers using table cloning

You can see a working demo at http://jaimonblog.appspot.com/datascroller/fixedHeaderFullClone.html

Download fxheader1.js and include it in your project as explained on the implementation section

How does it work?

• First we put a scrollable div container around the table element as in our first solution.
  • create a div element
  • clone the table element using cloneNode(true)
  • added the cloned table to this div
  • replace the table element with this div
• Create a container on top of the table to place the headers.
• Attach scrollHeader function to the table container div’s onscroll event, so that we can align the heading when the table is scrolled horizontally.
• We then clone the table and place it in the header container. Container height is set, so that only the header row is visible.
• We then set a negative margin top on the original table to hide the actual header.
• Attach fxheader function to window onresize event, so it works when window get resized.

Please note that, there are more than one way to do add a div element around our table element using JavaScript. You could speed up the process by adding these divs manually on the page as in Solution 1, because cloneNode function can be expensive. Make sure to use the correct IDs, so that rest of the code can find these. Please see the function addScrollerDivs in fxheader1.js for more details.

Solution 3: Scrolling with fixed headers using fast table cloning

You can see a working demo at  http://jaimonblog.appspot.com/datascroller/fixedHeaderFastClone.html

Download fxheader2.js and include it in your project as explained on the implementation section to get started.

Solution 2 will give you very accurate column widths at the expense of doing a full table cloning. If you have a table with lots of rows, this can take a while. If your rows have elements with unique IDs, you will have to change it on the cloned node to avoid  ID collision. Although it will work, it will lead to a sluggish user experience on pages with really large tables.

In solution 3, we are doing a fast clone without any child elements. Then we add the first row to it and set individual column width separately based on the offsetWidth property of each cell. You’ll have to offset cell margin/padding when setting the width. In our example, I deduct 3 from offsetWidth and that works fine for our table in all browsers I’ve tested.

Everything else is similar to solution 2.

Solution 4: Adding scrolling to table generated by ADF Faces 10g with fixed header (With and without pagination support) and automatic height stretching

Although in theory it is similar to solution 3, I had to make a few changes to make it work for a table generated by ADF Faces. The problem is ADF Faces creates three HTML tables for each af:table element. First and third tables are created for pagination support. It doesn’t create an ID for the actual data table itself, so we need to access it as a childNode of the container element. If pagination is there, we need to place this above our fixed header. Since we have the scrolling functionality, I thought the second pagination controls below the data table is not necessary, and I’m removing it from the page.

When cloning table data here, we have to update ID field of each element to avoid ID collision. We also have to set the correct selected index value for pagination selector combo box. Another functionality I’ve implemented here is the ability to auto stretch the table content to fit the page. You should pass in the ID of your last container component to make it work. Please see adjustHeight function in fxheader.js for more details.

As with the second and third solutions, you could add the following line to your JSPX page to get this working.

<afh:script source="fxheader.js" />
<afh:script text="fxheaderInit('testTable','footerContent');" partialTriggers="testTable" />

 

Where testTable is the ID of your af:table element and footerContent is the ID of your last container component for stretching. Partial Triggers are required here if used with pagination.

You can download a fully functioning JDeveloper project from http://jaimonblog.appspot.com/datascroller/ADF10gScroller.zip

Please note that it is created with  JDeveloper version 10.1.3.3. If you are using 11g, then fixed header functionality is already part of it. (Although there are a few issues with it at the time of writing this. One such issue is discussed here http://forums.oracle.com/forums/message.jspa?messageID=4032492#4032492)

As I’m not able to provide a demo link, you can see some screen shots of this solution here,