You can access custom data attributes in JavaScript using the dataset property. This property gives you access to all the data attributes on an element as a JavaScript object. For example, if you have an element with the attribute data-test=”value”, you can access it in JavaScript with element. dataset.

An HTML attribute is a piece of markup language used to adjust the behavior or display of an HTML element. For example, attributes can be used to change the color, size, or functionality of HTML elements.

The syntax for id is: write a hash character (#), followed by an id name. Then, define the CSS properties within curly braces {}.

Definition and Usage The default attribute is a boolean attribute. When present, it specifies that the track is to be enabled if the user's preferences do not indicate that another track would be more appropriate. Note: There must not be more than one <track> element with a default attribute per <media> element.