Xml
The meaning of XML: Extensible Markup Language, designed to: transfer data
HTML meaning: Hypertext Markup Language, designed to: Display the data
The two of them are designed to be different.
All two of them are markup languages, and the similarity is relatively high.
HTML is suitable for transmission in the Internet Web page, because every time you visit the page, will be the content of this page, get, through the app protocol, to our client to display, so the HTML comparison for attp transmission.
XML is about the same as HTML, so he also works with attp transmissions.
So the purpose of XML is to transfer data across platforms between different applications, or between different platforms, that is to say, the PHP language can send XML, or it can receive and parse.
Take him to another language, for example:. Net
In Java it is also possible to send XML data, or to receive XML data, so XML data can be passed across platforms, passing data to use.
Jaon is also applicable in this way, but compared with the two words, Jaon generally, is a lightweight data that transmits lightweight data. This XML is suitable for transferring heavyweight data with a large amount of data.
How are XML documents defined and what are the characteristics???
Composed of labels
Characteristics:
"1" tag name can be defined by itself
"2" an XML document, must have a root (there is only one). No more, no less.
Must have a root?? What do you mean??
The HTML document has a root
"3" XML document, although tag name can be defined by itself, but note: As long as there is a start tag, there must be an end.
XML documents, which are used by double tags, must correspond to the beginning and end. You can't leave the end out of the drain.
"4" is in the XML document and is case sensitive.
Cannot precede the beginning with uppercase, followed by the end in lowercase. The front uppercase must be capitalized, followed by lowercase.
PHP------XML