The <main> tag specifies the main content of a document.
The content inside the <main> element should be unique to the document. It should not contain any content that is repeated across documents such as sidebars, navigation links, copyright information, site logos, and search forms.
Note: There must not be more than one <main> element in a document. The <main> element must NOT be a descendent of an <article>, <aside>, <footer>, <header>, or <nav> element.
The numbers in the table specify the first browser version that fully supports the element.
The <main> tag is new in HTML5.
The <main> tag also supports the Global Attributes in HTML.
The <main> tag also supports the Event Attributes in HTML.