What is meaning of rel & type attribute and others in the Seeing is believing? I don't understand

<link type="text/css" rel="stylesheet" href="stylesheet.css"/>

<div id="header">
		<div id="navbar">


You can read bout those attributes here, the rel attribute: This attribute names a relationship of the linked document to the current document. Type tells us the type of document, in this case css, but you also have type="text/javascript", for javascript document