Any element conneced to a HTML form by FORM attribute

Data of textArea1:
Data of t1:

Above two input elements are outside the <form>..</form> , but they are part of the form by the form attribute ( form=f1) , here f1 is the ID of the form

HTML

<form method=post action='' id=f1><input type='submit' value='Submit'></input></form>

<TextArea name='textArea1' rows='3' cols='70' required=true form=f1></TextArea><br><br>
<input type=text name=t1 form=f1 required=true>