Implement validate function in external JavaScript file. This function will, when the submit button is clicked, check to see that the first name and last name fields are not empty. In addition, the email address textfield will be tested to ensure that the entry is a valid email (research email validation in JavaScript, and choose your preferred algorithm. Include a citation of the website from where you got the function in a comment in the JavaScript (.js) file). If the data entered are valid, save the entries to the JavaScript object entries. Include 'optIn' and 'accountType'. Confirm that an alert shows the entered data correctly. In the JS file, include comments of citations for retrieving values from a select or radio button, if used. Apply your choice of CSS to the defined classes (see html file, elements with class attributes).