What is the use of <div> tag??
Divisions. Div's are used to define 'virtual fences' around related content--blocks--including additional div's, and tend to be used for static and dynamic positioning, applying styles, etc.
The <div> tag defines a division or a section in an HTML document. The <div> tag is used to group block-elements to format them with CSS. ... Tip: The <div> element is very often used together with CSS, to layout a web page.