Search results
Results from the WOW.Com Content Network
In HTML syntax, an attribute is added to a HTML start tag. Several basic attributes types have been recognized, including: (1) required attributes needed by a particular element type for that element type to function correctly; (2) optional attributes used to modify the default functionality of an element type; (3) standard attributes supported ...
In SGML, HTML and XML documents, the logical constructs known as character data and attribute values consist of sequences of characters, in which each character can manifest directly (representing itself), or can be represented by a series of characters called a character reference, of which there are two types: a numeric character reference and a character entity reference.
HTML attributes define desired behavior or indicate additional element properties. Most attributes require a value. In HTML, the value can be left unquoted if it does not include spaces (attribute=value), or it can be quoted with single or double quotes (attribute='value' or attribute="value"). In XML, those quotes are required.
Incorrect HTML entity escaping may also open up security vulnerabilities for injection attacks such as cross-site scripting. If HTML attributes are left unquoted, certain characters, most importantly whitespace, such as space and tab, must be escaped using entities. Other languages related to HTML have their own methods of escaping characters.
The alt attribute is the HTML attribute used in HTML and XHTML documents to specify alternative text (alt text) that is to be displayed in place of an element that cannot be rendered. The alt attribute is used for short descriptions, with longer descriptions using the longdesc attribute .
Initially code-named "Cougar", [18] HTML 4.0 adopted many browser-specific element types and attributes, but also sought to phase out Netscape's visual markup features by marking them as deprecated in favor of style sheets. HTML 4 is an SGML application conforming to ISO 8879 – SGML. [20] April 24, 1998
Examples of this include nesting a "ul" element directly inside another "ul" element for any of the HTML 4.01 or XHTML DTDs. Dan Connolly cites the use of title element outside the head section. [1] Use of proprietary or undefined elements and attributes instead of those defined in W3C recommendations.
In data sanitization, HTML sanitization is the process of examining an HTML document and producing a new HTML document that preserves only whatever tags and attributes are designated "safe" and desired. HTML sanitization can be used to protect against attacks such as cross-site scripting (XSS) by sanitizing any HTML code submitted by a user.