about Div

This tag is useful in web designing, I collect some information about it.
Definition and Usage
This tag defines a division/section in a document.
Differences Between HTML and XHTML
The "align" attribute of the div element was deprecated in HTML 4.01.
The "align" attribute of the div element is not supported in XHTML 1.0 Strict DTD.
Tips and Notes
Note: Browsers usually place a line break before and after the div element.
Tip: Use this(div) tag to group block-elements to format them with styles.
Optional Attributes
DTD indicates in which DTD the attribute is allowed. S=Strict, T=Transitional, and F=Frameset.
at http://www.w3schools.com/tags/tag_div.asp