When using the xhtml1-transitional.dtd
doctype, collecting a credit card number with the following HTML
<input type="text" id="cardNumber" name="cardNumber" autocomplete='off'/>
will flag a warning on the W3C validator:
there is no attribute "autocomplete".
Is there a W3C / standards way to disable browser auto-complete on sensitive fields in a form?
Not ideal, but you could change the id and name of the textbox each time you render it - you'd have to track it server side too so you could get the data out.
Not sure if this will work or not, was just a thought.
If you use jQuery, you can do something like that :
and use the autocompleteOff class where you want :
If you want ALL your input to be
autocomplete=off
, you can simply use that :Note that there's some confusion about location of the autocomplete attribute. It can be applied either to the whole FORM tag or to individual INPUT tags, and this wasn't really standardized before HTML5 (that explicitly allows both locations). Older docs most notably this Mozilla article only mentions FORM tag. At the same time some security scanners will only look for autocomplete in INPUT tag and complain if it's missing (even if it is in the parent FORM). A more detailed analysis of this mess is posted here: Confusion over AUTOCOMPLETE=OFF attributes in HTML forms.
No, but browser auto-complete is often triggered by the field having the same
name
attribute as fields that were previously filled out. If you could rig up a clever way to have a randomized field name, autocomplete wouldn't be able to pull any previously entered values for the field.If you were to give an input field a name like "
email_<?= randomNumber() ?>
", and then have the script that receives this data loop through the POST or GET variables looking for something matching the pattern "email_[some number]
", you could pull this off, and this would have (practically) guaranteed success, regardless of browser.Here is a good article from the MDC which explains the problems (and solutions) to form autocompletion. Microsoft has published something similar here, as well.
To be honest, if this is something important to your users, 'breaking' standards in this way seems appropriate. For example, Amazon uses the 'autocomplete' attribute quite a bit, and it seems to work well.
If you want to remove the warning entirely, you can use JavaScript to apply the attribute to browsers that support it (IE and Firefox are the important browsers) using
someForm.setAttribute( "autocomplete", "off" ); someFormElm.setAttribute( "autocomplete", "off" );
Finally, if your site is using HTTPS, IE automatically turns off autocompletion (as do some other browsers, as far as I know).
Update
As this answer still gets quite a few upvotes, I just wanted to point out that in HTML5, you can use the 'autocomplete' attribute on your form element. See the documentation on W3C for it.
I would be very surprised if W3C would have proposed a way that would work with (X)HTML4. The autocomplete feature is entirely browser-based, and was introduced during the last years (well after the HTML4 standard was written).
Wouldn't be surprised if HTML5 would have one, though.
Edit: As I thought, HTML5 does have that feature. To define your page as HTML5, use the following doctype (i.e: put this as the very first text in your source code). Note that not all browsers support this standard, as it's still in draft-form.