File Input accept Attribute

By  on  

The HTML5 revolution provided us several simple but important attributes like download, autofocus, required, novalidate, and placeholder.  There's another one you may want to know about:  accept.  The accept attribute is useful for input[type=file] elements.  Let's have a look at it!

The HTML

I'll use Twitter's upload button to illustrate a good usage of the accept attribute:

<input type="file" name="media_empty" accept="image/gif,image/jpeg,image/jpg,image/png,">

The accept attribute gets a comma-separated list of mime types for files desired file types.  In this case, Twitter is allowing the user to upload common image formats.

Recent Features

  • By
    Regular Expressions for the Rest of Us

    Sooner or later you'll run across a regular expression. With their cryptic syntax, confusing documentation and massive learning curve, most developers settle for copying and pasting them from StackOverflow and hoping they work. But what if you could decode regular expressions and harness their power? In...

  • By
    5 Ways that CSS and JavaScript Interact That You May Not Know About

    CSS and JavaScript:  the lines seemingly get blurred by each browser release.  They have always done a very different job but in the end they are both front-end technologies so they need do need to work closely.  We have our .js files and our .css, but...

Incredible Demos

  • By
    Growl-Style Notifications Using MooTools Roar

    When I think of premier MooTools plugin developers, Harald "digitarald" Kirschner is usually one of the first people that come to mind. Harald has built some of MooTools' most popular plugins, including AutoCompleter, FancyUpload, and History Manager. My favorite plugin created...

  • By
    Submit Button Enabling

    "Enabling" you ask? Yes. We all know how to disable the submit upon form submission and the reasons for doing so, but what about re-enabling the submit button after an allotted amount of time. After all, what if the user presses the "stop"...

Discussion

  1. The biggest problem about using this code is that the user can change it easily with firebug or others debugs.

    • Matthew

      It’s not for validation, it’s for assisting the user to select the right file type (since the file selection will only show files of that type).

      You should never use this for validation since some browsers do not support it.

    • Validation should be done on your backend. This kind of selection only helps users what we really need from them.

  2. Be careful with this.

    The main issue is that some mobile browsers started to prevent the user from selecting any (!) file at all if the accept property was declared (which is just plain terrible user agent behaviour).

    Thus if you want to support these browsers, you have to detect them and remove the accept property.

    For details see http://caniuse.com/#feat=input-file-accept

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!