XML Learning Notes

1. The XML Extensible Markup Language is used to mark electronic files with a structured markup language that can be used to tag data, define data types, and is a source language that allows users to define their own markup language (allowing user customization).

2, Cdata:character Data role: The label as plain text content, syntax: <! [cdata[content]]>, because the normal <> symbol content will be considered, so use it to label such as:

Run the result as
3, DTD constraint: Document Type Definition,xml Technology, you can write a file to constrain an XML writing specification, which is called a constraint. The constraint document defines the element names, attributes, and the order in which elements appear in the XML, and so on. The common constraint techniques are XML DTD, XDR, SOX, XML Schema. DTD storage location is divided into: file, external file
File such as: "+" means that Provence can have more than one label, no "+" words can only have a label, "#PCDATA" means to fill in the text data, such as the name tag under the PHP

See the DTD seems to be somewhat familiar, is not in the ordinary HTML document writing seen, the original HTML document <! DOCTYPE > is a constraint technology.

XML Learning Notes