XML is a "markup" language that is similar to HTML. "Markup" means that information can be identified (or "tagged") using a special characters that have special meaning.
For example, to identify the word "Bob" as a "name" we can write:
Basically, stuff that is wrapped by greater-than and less-than symbols are "tags." Tags are used to organize and define structure. Browsers and other software such as Pickle use these tags to extract and manipulate the data that is located between the tags.
There are two kinds of tags: Opening Tags and Closing Tags. An "opening tag" is used as a marker to introduce data. The "closing tag" is a marker used to terminate the data. One way to exemplify this is: In the English language, we use a capital letter to introduce a new sentence, and a period to terminate a sentence.
Greater-than, less-than and a forward slash symbols have special meaning. The greater-than and less-than symbols define a tag. The forward slash is a marker indicating that the tag that the forward slash is used within is a closing tag.
The following illustration attempts to explain each element of the structure visually:
opening tag data closing tag
___________ _______ ___________
< name > bob < / name >
_ ____ _ ___ _ _ ____ _
1 2 3 4 5 6 7 8
1) The opening "greater than" symbol means "I'm starting to define a tag."
2) The word is used to identify or label the tag.
3) The closing "less than" symbol means "I'm done labeling this tag."
4) The actual data that you are attempting to store or present
5) The opening "greater-than" symbol means "I'm starting to define a tag."
6) The Forward slash signifies that this tag is a closing tag.
7) The same word used in the opening tag must be used within the closing tag to identify the tag's label.
8) The closing "less-than" symbol closes the tag.