Placeholders supplementary, warn against polyfill

posts/input-placeholder.md

@@ -1,9 +1,14 @@
 feature: input[placeholder]
-status: use
+status: caution
 tags: gtie9
 kind: html
 polyfillurls:[Placeholder jQuery Plugin](https://github.com/mathiasbynens/jquery-placeholder)
 
 Input placeholders are simply ignored in IE 9 and below. Note that they are only applied when the **type** of the input is *text*, *password*, *search*, *tel*, *url*, or *email*. *Textareas* can have placeholders, too. Otherwise, it is ignored.
 
+Per the [HTML specification](http://dev.w3.org/html5/spec/Overview.html#the-placeholder-attribute):
+> The placeholder attribute represents a short hint (a word or short phrase) intended to aid the user with data entry. A hint could be a sample value or a brief description of the expected format. The placeholder attribute should not be used as an alternative to a label.
+
 `input[placeholder]` is commonly the first polyfill anyone writes and, as such, there are [many of them](http://bit.ly/polyfills). Password inputs and submit event clearing are among many of the gotchas that catch naive implementations; Mathias's polyfill below handles these cases very well.
+
+That said, a properly implented form should have labels and any placeholders should be supplementary.  As such, they are not required for successful completion of a form and use of a polyfill is likely unwarranted.