HTML and CSS Reference
In-Depth Information
section unambiguously. Specifically, the value must begin with a letter,
and can contain letters, numbers, hyphens, colons, underscores, and
periods, but not spaces. Although we're introducing it within the context
of the <div> tag, this attribute can be used with almost any tag.
When used as an element label, the value of the id attribute can be ad-
ded to a URL to address the labeled element uniquely within the docu-
ment. You can label both large portions of content (via a tag like <di-
v> ) and small snippets of text (using a tag like <i> or <span> ). For ex-
ample, you might label the abstract of a technical report using <div
id="abstract"> . A URL could jump right to that abstract by referencing
report.html#abstract . When used in this manner, the value of the id at-
tribute must be unique with respect to all other id attributes within the
document and all the names defined by any <a> tags with the name at-
tribute. [ Linking Within a Document, 6.3.3 ]
When used as a stylesheet selector, the value of the id attribute is the
name of a style rule that can be associated with the current tag. This
provides a second set of definable style rules, similar to the various style
classes you may create. A tag can use both the class and the id attrib-
utes to apply two different rules to a single tag. In this case, the name
associated with the id attribute must be unique with respect to all other
style IDs within the current document. You can find a more complete
description of style classes and IDs in Chapter 8 . The title attribute
Use the optional title attribute and quote-enclosed string value to as-
sociate a descriptive phrase with the division. Like the id attribute, the
title attribute can be used with almost any tag and behaves similarly
for all tags.
There is no standards-defined usage for the value of the title attribute,
but current browsers display the title when the mouse pauses over that
elementin this case, anywhere in the <div> -defined text area. For ex-
Search WWH ::

Custom Search