Rather than confusing to post what ... I try to answer questions about HTML5 Validation. Among the frequent questions, namely: My blog is valid, but why still appear first warning?
Maybe my friend often seen sightings like this:
Warning that usually appear in http://validator.w3.org/ because this site is widely used for HTML5 validation checks. Though there are many websites that provide this HTML5 validation tool.
Apart from the use of other sites, actually these questions already have the answer on the site such as this:
The validator checked your document with an experimental feature: HTML5 Conformance Checker. This feature has been made available for your convenience, but be aware that it may be unreliable, or not perfectly up to date with the latest development of some cutting-edge technologies. If you find any issues with this feature, please report them. Thank you.
Meaning that rather please translate itself. But the point that 1 Warning is stated that this is only an experimental validation tool, meaning no absolute 100% valid even as technology growing interest it did not rule out a change in the structure of the HTML.
Actually I personally still a little confused with this HTML5 validator. Sometimes I tried on one site is valid, but other sites are invalid. For example Manipulation In comments by using the rel tag. In http://html5.validator.nu/ detected as an error, but in http://validator.w3.org/ is valid (passed). Maybe also because there are some differences in this, comes the first warning.
