Xml
Five. Meta data (METADATA)---Professional XML users work with meta data.
In HTML we know that you can use META tags to define keywords for Web pages, profiles, etc., which are not displayed in the Web page, but can be searched by search engines and affect the order in which search results are sorted.
XML deepens and expands on this principle, in XML, where you can describe your information, you can validate information through meta, perform a search, force a display, or process other data.
Here are some of the uses of XML metadata in practical applications:
1. Digital signatures can be validated to make the online Business submission action (submission) effective.
2. Can be easily indexed and more efficient search.
3. Data can be transmitted between different languages.
The consortium is working on a metadata approach called RDF (Resource Description Framework) that automatically exchanges information, and the consortium claims that using RDF in conjunction with digital signatures will allow for "authentic" e-business in the network.
Six. Show
XML cannot display pages alone, and we use formatting techniques, such as CSS or XSL, to display documents created by XML tags.
In the first chapter we talked about XML as separating data from format. The XML document itself does not know how to display, and must have a secondary file to help implement it. (XML cancels all identities, including style definition identities such as font,color,p, so XML is all about using a method like DHTML CSS to define document style styles.) ), the file types used in XML to set display style styles are:
1.XSL
The XSL full name is the extensible Stylesheet Language (Extensible Style language), the primary file type for future design of XML document display styles. It is also based on the XML language itself. With XSL, you can flexibly set the document display style, and the document will automatically adapt to any browser and PDA (palmtop).
XSL can also convert XML to HTML, so older browsers can also browse XML documents.
2.CSS
CSS is familiar, the full name is cascading style Sheets (cascading style sheet), is currently used to display XML documents on the browser the Main method.
3.Behaviors
Behaviors has not become a standard yet. It is a unique feature of Microsoft's IE browser, with which you can set some interesting actions on the XML identity.
Seven. DOM
Dom is the Document Object model, what is DOM used for? If you think of your document as a separate object, Dom is the standard for manipulating and controlling the object in HTML or XML.
Object-oriented methods of thinking have been very popular, in programming languages (such as JAVA,JS), the use of object-oriented programming ideas. In XML, to manipulate and control a Web page as an object, we can build our own objects and templates. The API is used to communicate with objects and to command objects. The API full name application programming Interface, which is the rule for accessing and manipulating objects. Dom is an API that describes the rules of Html/xml document objects in detail. It prescribes the naming conventions, program models, and communication rules for Html/xml document objects. In an XML document, we can treat each identity element as an object---it has its own name and attributes.
XML creates identities, and Dom's role is to tell the script how to manipulate and display these identities in a browser window
Here we have a brief overview of some of the fundamentals of XML, and let's look at how they relate to each other and how they work, first look at a picture here:
--> !--? xml:namespace prefix = o ns = "Urn:schemas-microsoft-com:office:office"/-->
1.XML describes the data type. For example: "King Lear" is a headline element;
2.CSS stores and controls the display style of the element. For example: The title will be displayed in 18pt font
The 3.script script controls how the element acts. For example: When a TITLE element "out of the stock" is displayed in red.
4.DOM provides a common platform for the exchange of scripts and objects, and displays the results in a browser window.
If any part of the error occurs, it will not get the correct result.
Well, seeing here, we've got a general idea of how XML works. Through this chapter of study, we may feel that XML seems to be more biased data processing, more convenient for programmers to learn. In fact, the purpose of XML design is to facilitate the sharing and interaction of data. In the next chapter, we will systematically learn about the various terms of XML.
