HTML and CSS Reference
• The http-equiv attribute is also used for page ratings, cache control, setting
defaults such as language or scripting, and a variety of other tasks. In many cases, it
would be better to set these values via the actual HTTP headers rather than via a
• The <meta> tag can be used arbitrarily by site owners, search services, and browser
vendors. For example, when defining pages for Apple's iPhone, the viewport and
format-detection values for a <meta> tag can be set to control presentation on
the device. Google uses a verify-v1 value for approving sites for some
Webmaster-related features. Many more examples can be found online; the point is
that the element is quite flexible and has numerous uses.
• The HTML 2.0 and 3.2 specifications define only the content , http-equiv , and
• The meanings of some HTML5 common attributes (particularly those that are
interface-oriented, such as accesskey , dragable , and spellcheck ) are quite
unclear. The specification currently puts these attributes everywhere, unlike HTML 4,
which does remove core attributes when context is inappropriate. Do not be
surprised if they are removed from some HTML5 elements in future revisions to the
• The HTML5 specification states that the http-equiv attribute should not set
Content-Language values; the lang attribute should be used in the document
<meter> (Scalar Gauge)
This HTML5 element defines a scalar measurement within a known range, similar to what
might be represented by a gauge.
HTML5 Standard Syntax
accesskey="spaced list of accelerator key(s)"
contenteditable="true | false | inherit"
contextmenu="id of menu"
dir="ltr | rtl"
draggable="true | false | auto"
id="unique alphanumeric identifier"
itemid="microdata id in URL format"
itemref="space-separated list of IDs that may contain microdata"
itemtype="microdata type in URL format"