W3C home > Mailing lists > Public > www-validator@w3.org > July 2014

Re: couple of comments on the Markup Validation Service

From: Jukka K. Korpela <jkorpela@cs.tut.fi>
Date: Fri, 25 Jul 2014 15:31:39 +0300
Message-ID: <53D24E2B.9010803@cs.tut.fi>
To: Edward Vassar <ervassar@gmail.com>, www-validator@w3.org
2014-07-23 3:02, Edward Vassar wrote:

> A piece of html that I wrote provoked the validation service to flag a
> plythera of errors of 3 types.

Generally, you should include a URL of the document.

> None of the flagged "errors"
> seem to prevent desired code execution.

They point out that the effects may differ from what you expect,

> First error type involved using "size attribute for input types file and
> number: Error/Line 20 <http://validator.w3.org/check#line-20>, Column
> 84/: Attribute size not allowed on element input at this point.
> |actual code:|<input type="file" id="approvalInputTypeFile" multiple accept="image/*" size="80">

The size attribute in such an element has had different definitions in 
specifications and different implementations in browsers. This is why it 
has been removed from HTML5, which appears to be what you are validating 

> <!--validate doesn't like using size if type is file, but how else control the field size -->

It is expected to be controlled by the browser. It depends on the 
implementation whether there is a file name box at all and what the file 
name syntax there is, hence how wide it needs to be.

But you can set the width of the element in CSS.

> likewise for <input type="number" id="numImageId" size="3" value="6"
> min="1"> <!--validate doesn't like using size if type is number, but how
> else control the field size -->

Similarly, the browser is expected to present some kind of widget for 
numeric input. For numbers, you are not expected to specify the length 
in characters but the limits, e.g. max="999".

However, the validator is in error. It should not issue an error 
message, but a warning. Using the size attribute in this context is 
explicitly declared as conforming, though obsolete:

Note that HTML5 validation is experimental, HTML5 itself is work in 
progress, and there is no definitive statement about the version of 
HTML5 that the validator checks against. I have mentioned an HTML 5.1 
Nightly URL above, since the validator's error messages refer to that 
version of HTML5.

> The other two errors were objections to <img>s with no src or alt.

They have long been required in HTML. HTML5 has some debatable 
statements about alt not being required in all contexts, but they are 
best ignored.

> My
> HTML supplied placeholder <img> locations.  The JS supplied the actual
> src and alt for each location that was utilized at any particular point
> in time.

This means that when scripting is disabled, there are dysfunct <img> 
elements. Browsers may render them in various ways; there are no strict 
rules for such error handling. So you should either fill in such values 
that the page makes some sense when they are actually used (when 
scripting is disabled), or generate and insert the img elements with 
JavaScript. You don't need an invalid dummy <img> tag, when you can just 
document.createElement('img') etc.

Received on Friday, 25 July 2014 12:32:14 UTC

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