The HTML 5 Geolocation API allows you to access the location of the user. For privacy, user agents asks the permission of user before accessing the location details.
The HTML data global attribute, introduced in HTML 5, is used to embed custom data to the HTML elements.
The HTML s tag displays text with a line through it. This tag is used to denote text that is no longer accurate or relevant. It should not be used to represent deleted text. To represent deleted text, use del tag.
The HTML time tag is used to represent date or time. The main advantage of using time tag is that it can also be used to encode date/time in machine-readable format so that the user agent can offer to add events and reminders.
The HTML var tag (variable) is used to represent variable names. Most browsers display its content in italics.
The HTML fieldset tag is used to group similar items in a web form. The legend tag is used to set the caption for a fieldset.
An HTML optgroup tag is used to group options inside a select tag.
The HTML select tag is used to create a drop-down list. Each items in the list is defined using option tag, nested inside the select tag.
The HTML progress tag is used to display indicator (typically a progress bar) showing the progress of a task.
The HTML meter tag is used for indicating a scalar measurement within a known range, or a fractional value.