The HTML5 <hr> tag is an integral part within the content of a document. It is mainly used so that the break which changes the theme or topic of the content can be shown clearly and users would not feel confused.
There is little difference when it comes to the use of HTML5 <hr> tag. In HTML5, the <hr> tag is considered as a thematic break. On the other hand, in HTML4, it is considered as a horizontal rule.
Technically, in HTML4.01 the <hr> tag is used more for presentation. On the other hand, HTML5 sees it as an element of semantics.
In some occasions, the HTML5 <hr> tag is still reflected as a horizontal rule, especially in visual browsers. However, the styles in HTML4 like the align, nonshade, styles and other formatting actions are considered obsolete. Hence, these are no longer carried over to HTML5. The HTML5 <hr> tag is formatted by using CSS.
The HTML5 <hr> tag is supported in primary browsers like Firefox, Google Chrome, Safari, Internet Explorer and Opera. The HTML5 <hr> tag is also compatible with the Global Attributes in HTML5. Even the Event Attributes is supported by HTML5 <hr> tag.