revision:
When present, it specifies that the element should be disabled. A disabled element is unusable. The disabled attribute can be set to keep a user from using the element until some other condition has been met (like selecting a checkbox, etc.). Then, a JavaScript could remove the disabled value, and make the element usable again.
The disabled attribute can be used on the following elements: <button>, <fieldset>, <input>, <optgroup>, <option>, <select>, <textarea>.
<element disabled></element>
Disabled <input> elements in a form will not be submitted! The disabled attribute is usually drawn with grayed-out text. If the element is disabled, it does not respond to user actions, it cannot be focused.
<button style="margin-left:5vw;" type="button" disabled>Click Me!</button>
<br><br>
<form style="margin-left:5vw;" action="action_page.php">
<label for="cars">Choose a car:</label>
<select name="cars" id="cars" disabled>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="mercedes">Mercedes</option>
<option value="audi">Audi</option>
</select>
<br><br>
<input type="submit" value="Submit">
</form>
<form style="margin-left:5vw;">
<form style="margin-left:5vw;" action="action_page.php">
<fieldset disabled>
<legend>Personalia:</legend>
<label for="fname">First name:</label>
<input type="text" id="fname" name="fname"><br><br>
<label for="lname">Last name:</label>
<input type="text" id="lname" name="lname"><br><br>
<label for="email">Email:</label>
<input type="email" id="email" name="email"><br><br>
<label for="birthday">Birthday:</label>
<input type="date" id="birthday" name="birthday"><brs><br>
<input type="submit" value="Submit">
</fieldset>
</form>
</form>