DHTML and XML

Dynamic HyerText Markup Language (DHTML) is a combination of Web development technologies used to create dynamically changing websites. Web pages may include animation, dynamic menus and text effects. The technologies used include a combination of HTML, JavaScript or VB Script, CSS and the document object model (DOM). 

Designed to enhance a Web user’s experience, DHTML includes the following features: 

• Dynamic content, which allows the user to dynamically change Web page content
• Dynamic positioning of Web page elements
• Dynamic style, which allows the user to change the Web page’s color, font, size or content

XML

• XML is a software- and hardware-independent tool for storing and transporting data.
• XML stands for eXtensible Markup Language
• XML is a markup language much like HTML
• XML was designed to store and transport data
• XML was designed to be self-descriptive

Difference Between XML and HTML

• XML and HTML were designed with different goals:
• XML was designed to carry data - with focus on what data is
• HTML was designed to display data - with focus on how data looks
• XML tags are not predefined like HTML tags are
• The XML language has no predefined tags.XML tags are defined by the author of the XML document.
• HTML works with predefined tags like <p>, <h1>, <table>, etc.

XML Vocabulary

Character: An XML document is a string of characters. Almost every legal Unicode character may appear in an XML document.

Processor and application: The processor analyzes the markup and passes structured information to an application. The specification places requirements on what an XML processor must do and not do, but the application is outside its scope. The processor (as the specification calls it) is often referred to colloquially as an XML parser.

Markup and content: The characters making up an XML document are divided into markup and content, which may be distinguished by the application of simple syntactic rules. Generally, strings that constitute markup either begin with the character < and end with a >, or they begin with the character & and end with a; A tag is a markup construct that begins with < and ends with >. 

start-tag, such as <section>;

end-tag, such as </section>;

Element: 

An element is a logical document component that either begins with a start-tag and ends with a matching end-tag or consists only of an empty-element tag. The characters between the start-tag and end-tag, if any, are the element's content, and may contain markup, including other elements, which are called child elements. An example is <greeting>Hello, world!</greeting>. Another is <line-break />.

Attribute

An attribute is a markup construct consisting of a name–value pair that exists within a start-tag or empty-element tag. An example is <img src="madonna.jpg" alt="Madonna" />, where the names of the attributes are "src" and "alt", and their values are "madonna.jpg" and "Madonna" respectively. Another example is <step number="3">Connect A to B.</step>, where the name of the attribute is "number" and its value is "3". An XML attribute can only have a single value and each attribute can appear at most once on each element. In the common situation where a list of multiple values is desired, this must be done by encoding the list into a well-formed XML attribute[note 1] with some format beyond what XML defines itself. Usually this is either a comma or semi-colon delimited list or, if the individual values are known not to contain spaces,[note 2] a space-delimited list can be used. <div class="inner greeting-box">Welcome!</div>, where the attribute "class" has both the value "inner greeting-box" and also indicates the two CSS class names "inner" and "greeting-box".

XML declaration

XML documents may begin with an XML declaration that describes some information about themselves. An example is 
<?xml version="1.0" encoding="UTF-8"?>.

<breakfast_menu>
<food>
<name>Punjabi</name>
<price>Rs. 120</price>
<description>Two Paranthas with Curd and Butter.</description>
<calories>1200</calories>
</food>
<food>
<name>South Indian</name>
<price>Rs 110</price>
<description> 1 Dosa 1 Idli 1 Vada with Samber</description>
<calories>900</calories>
</food>

<breakfast_menu>