Javascript – HTML table with fixed headers

csshtml-tablejavascript

Is there a cross-browser CSS/JavaScript technique to display a long HTML table such that the column headers stay fixed on-screen and do not scroll with the table body. Think of the "freeze panes" effect in Microsoft Excel.

I want to be able to scroll through the contents of the table, but to always be able to see the column headers at the top.

Best Answer

This can be cleanly solved in four lines of code.

If you only care about modern browsers, a fixed header can be achieved much easier by using CSS transforms. Sounds odd, but works great:

HTML and CSS stay as-is.
No external JavaScript dependencies.
Four lines of code.
Works for all configurations (table-layout: fixed, etc.).

document.getElementById("wrap").addEventListener("scroll", function(){
   var translate = "translate(0,"+this.scrollTop+"px)";
   this.querySelector("thead").style.transform = translate;
});

Support for CSS transforms is widely available except for Internet Explorer 8-.

Here is the full example for reference:

document.getElementById("wrap").addEventListener("scroll",function(){
   var translate = "translate(0,"+this.scrollTop+"px)";
   this.querySelector("thead").style.transform = translate;
});

/* Your existing container */
#wrap {
    overflow: auto;
    height: 400px;
}

/* CSS for demo */
td {
    background-color: green;
    width: 200px;
    height: 100px;
}

<div id="wrap">
    <table>
        <thead>
            <tr>
                <th>Foo</th>
                <th>Bar</th>
            </tr>
        </thead>
        <tbody>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
            <tr><td></td><td></td></tr>
        </tbody>
    </table>
</div>

Related Solutions

Javascript – Add table row in jQuery

The approach you suggest is not guaranteed to give you the result you're looking for - what if you had a tbody for example:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
</table>

You would end up with the following:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
  <tr>...</tr>
</table>

I would therefore recommend this approach instead:

$('#myTable tr:last').after('<tr>...</tr><tr>...</tr>');

You can include anything within the after() method as long as it's valid HTML, including multiple rows as per the example above.

Update: Revisiting this answer following recent activity with this question. eyelidlessness makes a good comment that there will always be a tbody in the DOM; this is true, but only if there is at least one row. If you have no rows, there will be no tbody unless you have specified one yourself.

DaRKoN_ suggests appending to the tbody rather than adding content after the last tr. This gets around the issue of having no rows, but still isn't bulletproof as you could theoretically have multiple tbody elements and the row would get added to each of them.

Weighing everything up, I'm not sure there is a single one-line solution that accounts for every single possible scenario. You will need to make sure the jQuery code tallies with your markup.

I think the safest solution is probably to ensure your table always includes at least one tbody in your markup, even if it has no rows. On this basis, you can use the following which will work however many rows you have (and also account for multiple tbody elements):

$('#myTable > tbody:last-child').append('<tr>...</tr><tr>...</tr>');

Javascript – Setting “checked” for a checkbox with jQuery

Modern jQuery

Use .prop():

$('.myCheckbox').prop('checked', true);
$('.myCheckbox').prop('checked', false);

DOM API

If you're working with just one element, you can always just access the underlying HTMLInputElement and modify its .checked property:

$('.myCheckbox')[0].checked = true;
$('.myCheckbox')[0].checked = false;

The benefit to using the .prop() and .attr() methods instead of this is that they will operate on all matched elements.

jQuery 1.5.x and below

The .prop() method is not available, so you need to use .attr().

$('.myCheckbox').attr('checked', true);
$('.myCheckbox').attr('checked', false);

Note that this is the approach used by jQuery's unit tests prior to version 1.6 and is preferable to using $('.myCheckbox').removeAttr('checked'); since the latter will, if the box was initially checked, change the behaviour of a call to .reset() on any form that contains it – a subtle but probably unwelcome behaviour change.

For more context, some incomplete discussion of the changes to the handling of the checked attribute/property in the transition from 1.5.x to 1.6 can be found in the version 1.6 release notes and the Attributes vs. Properties section of the .prop() documentation.