You have a generic bloc container with the div tag and a inline generic container with the span tag. Mostly a style attribute is bounded to a generic container for specifying the rendering or using a CSS rule.
Usual attributes
Attribute name
Attribute value
class
Set a value for CSS rules. The CSS rule will be applied to all tags with the same class name
id
Set a unique value, it is useful for JavaScript or for CSS rule. For CSS it will be applied only for this tag
style
Set a CSS value. It has always priority for general CSS rules. Sample : "background-color:red;color:white"