HTML attribute: Difference between revisions

Revision as of 08:08, 10 April 2013

Revision as of 12:39, 10 April 2013

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* The <code>id</code> attribute provides a document-wide unique identifier for an element.<ref>However, multiple identifiers may apply to the same element; in particular an element may be inside another element, each having an identifier.</ref> This can be used as [[CSS selector]] to provide presentational properties, by browsers to focus attention on the specific element, or by scripts to alter the contents or presentation of an element. Appended to the URL of the page, the URL directly targets the specific element within the document, typically a sub-section of the page. For example, the ID "Attributes" in <code><nowiki>http://en.wikipedia.org/wiki/HTML#Attributes</nowiki></code>

* The '''<code>class</code> attribute''' provides a way of classifying similar elements. This can be used for [[semantics|semantic]] or presentation purposes. Semantically, for example, classes are used in [[microformat]]s. Presentationally, for example, an HTML document might use the designation <code>class="notation"</code> to indicate that all elements with this class value are subordinate to the main text of the document. Such elements might be gathered together and presented as footnotes on a page instead of appearing in the place where they occur in the HTML source.

* An author may use the <code>style</code> non-attributal codes presentational properties to a particular element. It is considered better practice to use an element’s <code>id</code> or <code>class</code> attributes to select the element with a stylesheet, though sometimes this can be too cumbersome for a simple and specific or ad hoc application of styled properties.

* The <code>title</code> attribute is used to attach subtextual explanation to an element. In most browsers this attribute is displayed as what is often referred to as a [[tooltip]].