Thursday, April 30, 2009

How To : Styling a file type input

Of all form fields, the file upload field is by far the worst when it comes to styling. Explorer Windows offers some (but not many) style possibilities, Mozilla slightly less, and the other browsers none at all. The "Browse" button, especially, is completely inaccessible to CSS manipulation.

The Solution

Fortunately, reader Michael McGrady invented a very neat trick that allows us to (more or less) style file upload fields. The credits for the solution presented on this page are wholly his, I only added the position: relative, a few notes and tests, and ported it entirely to JavaScript.


McGrady's technique is elegant in its simplicity:

  1. Take a normal <input type="file"> and put it in an element with position: relative.
  2. To this same parent element, add a normal <input> and an image, which have the correct styles. Position these elements absolutely, so that they occupy the same place as the <input type="file">.
  3. Set the z-index of the <input type="file"> to 2 so that it lies on top of the styled input/image.
  4. Finally, set the opacity of the <input type="file"> to 0. The <input type="file"> now becomes effectively invisible, and the styles input/image shines through, but you can still click on the "Browse" button. If the button is positioned on top of the image, the user appears to click on the image and gets the normal file selection window.
(Note that you can't use visibility: hidden, because a truly invisible element is unclickable, too, and we need the <input type="file"> to remain clickable)

Until here the effect can be achieved through pure CSS. However, one feature is still lacking.

  • When the user has selected a file, the visible, fake input field should show the correct path to this file, as a normal <input type="file"> would. It's simply a matter of copying the new value of the <input type="file"> to the fake input field, but we need JavaScript to do this.

Therefore this technique will not wholly work without JavaScript. For reasons I'll explain later, I decided to port the entire idea to JavaScript. If you're willing to do without the visible file name you can use the pure CSS solution. I'm not sure if this would be a good idea, though.

The HTML/CSS Structure

I've decided on the following HTML/CSS approach:

div.fileinputs {
position: relative;
}

div.fakefile {
position: absolute;
top: 0px;
left: 0px;
z-index: 1;
}

input.file {
position: relative;
text-align: right;
-moz-opacity:0 ;
filter:alpha(opacity: 0);
opacity: 0;
z-index: 2;
}

<div class="fileinputs">
<input type="file" class="file" />
<div class="fakefile">
<input />
<img src="search.gif" />
</div>
</div>

For original article check at www.quirksmode.org