DIV VS SPAN

How do you know when to use the DIV element and when do you use SPAN?
In a nutshell, DIV is a block level element. In other words, you use it to define the characteristics you want a whole block of code to follow. It is used to break up sections of a page and it can contain additional tags. If you are familiar with HTML, the DIV element is very similar to the P (paragraph) element.
On the other hand, SPAN is an inline element. Inserting a SPAN tag into a line of code lets the browser know to apply the indicated style to a small section of text, but not to break the line. It cannot contain any additional elements. It is kind of like the old FONT element that you would apply in HTML.