The following explains the correct technical terms used for the World Wide Web languages. Often, these terms are incorrectly used, most notably the "alt tag" (there is no "alt tag" in HTML, only an "alt attribute").
HTML
In the markup-languages HTML (the HyperText Markup Language) and XHTML, the terms are:
| Element | p (paragraph) |
|---|---|
| Opening tag | <p> |
| Closing tag | </p> |
| Attribute Name | <p attribute="..."> |
| Attribute Value | <p attribute="value"> |
| Attribute Name-Value-Pair | attribute="value" |
An end tag might be optional and can be omitted in HTML. In XHTML, it can never be ommitted, but one can use empty-elements, such as
(the space before the ending slash is for downwards-compatibility and not needed in XML per se).
An attribute-value can not be omitted in HTML, actually, the attribute-name may be omitted. In XML, neither attribute-name nor attribute-value may be omitted (resulting in the somewhat strange double-pairs).
HTML, and XHTML, are not programming or scripting languages.
The differences between HTML and XHTML? The former is based on SGML, case-insensitive, and optional closing-tags may be omitted. XHTML on the other hand is based on XML, is case-sensitive, and doesn't include optional closing-tags for non-empty elements that. XHTML is an XML application.
Meta-Data in HTML, and XHTML, is not limited to the meta-element contained in the head-element. It is also including the title-element.
In XML and HTML DOM (Document Object Model) terms, two elements can be nested within each other. For example:
<p>This is an <em>example</em>.</p>
(We then speak of child-element, parent-node, sibling, and so on.)
Here, the paragraph (p-element) is a block-level element, because by default, in a visual rendering context, it creates a line-feed between itself and the next element. Also, it adheres to the CSS2 box-model layout and its properties (such as border or margin). The "em" element is an inline-level element, and can not contain block-level elements.
Also, there is sometimes confusion between the two DTDs: Document Type Declaration, and Document Type Definition. The declaration points to the definition. The declaration is typically named "doctype".
Furthermore, in XML (and XHTML), a document is well-formed when it is correct according to the XML syntax definition, and valid when it validates against the Document Type. In other words an XML document can be well-formed, but invalid, but never be not well-formed and still be valid; and also, a valid document is always also well-formed.
CSS
In the layout-language CSS, the Cascading StyleSheets language, the terms are:
- Selector
- Property
- Value
E.g. the following:
p
{
font-size: 110%;
}
... would be:
selector opening scope-delimiter property: value separator closing scope-delimiter
JavaScript
Then there is JavaScript, a scripting language. It is now standardized under the ECMAScript language family. JScript is Microsoft's version of Netscape's implementation, hence the alternate naming. The programming language Java, on the other hand, is not connected to JavaScript/ ECMAScript/ JScript language family, other than that the two share some common syntax characteristics. Java and JScript and so on can be both client-side as well as server-side languages.