The EM element is one of a large group of elements that the HTML 4.0 recommendation calls phrase elements. Such elements assign structural meaning to a designated portion of the document. An EM element is one that is to be rendered differently from running body text to designate emphasis.

Browsers have free rein to determine how (or whether) to distinguish EM element content from the rest of the BODY element. Both Navigator and Internet Explorer elect to italicize the text. This can be overridden with a style sheet as you see fit.