Don created a form that asks for the user's name and email address. He wants to test the user's input in the email textbox to verify that it contains an @ symbol. He uses the document.getElementByld$($email$\text{'}).$value to retrieve the input. What standard is this method based on$?$

A Application Programming Interface $($API$)$

B $$ Asynchronous JavaScript and XML $($AJAX$)$

C $$ Canvas Application Programming Interface $($API$)$

D Document Object Model $($DOM$)$