Note: If you don't know what an element/tag is and/or how you must use it we recommend you read our HTML tags and attributes tutorial, which you can find in our HTML tutorials section.
Table of contents
Bypass table of contentsThe HTML em element indicates an emphasis for its content. Although this emphasis is lower than the strong emphasis (HTML strong element), the text inside this element is supossed to be more important than the regular text.
Browsers usually render the content of this element with an italic font style to visually represent the emphasis. But, despite this, authors shouldn't confuse its semantic purpose with its usual visual representation.
The "id" attribute assigns an identifier to the associated element. This identifier must be unique in the document and can be used to refer to that element in other instances (e.g., from client-side scripts).
The "class" attribute assigns a class name (or a list of class names separated by spaces) to the container element. It is used together with style sheets and tells the browser the class (or classes) to which the element is associated.
A class gives presentational attributes to elements (read more at the Cascading Style Sheets tutorial).
This attribute is used to define presentational attributes for the containing element, and its value should be composed by style sheets properties. Although in some cases it can become useful, a better practice is to place presentational attributes in external files, relating them to elements with the "class" attribute. This way you keep the semantic and presentational parts of your document separated.
You can find more information about presentational attributes at the Cascading Style Sheets tutorial.
The purpose of this attribute is to provide a title for the element. Its value must be a short and accurate description of the element. Browsers usually render it as a "tool tip" when the user puts the mouse pointer over the element for a short period of time.
Specifies the language of an element's content. The default value is "unknown".
When writing XHTML 1.0 documents, the attribute used to specify the language of an elements is "xml:lang". For forward and backward compatibility both attributes can be used simultaneously as in the example below. Note that in XHTML 1.1 the "lang" attribute has been completely replaced by "xml:lang" and its use is no longer valid.
This attribute indicates the direction in which the texts of the element must be read. This includes content, attribute values and tables. It has two possible values that are case-insensitive:
See a complete list and information about events in HTML
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