Which attribute is used to specify that an input field must be filled out?

Which attribute is used to specify that an input field must be filled out?

• A. placeholder
• B. maxlength
• C. required
• D. pattern

Answer: (C)

The key idea is ensuring a field has a value before the form can be submitted. The attribute that does this is required. It’s a boolean attribute, so simply including it on an input (or textarea, or select) tells the browser that the field must be filled in. If the user leaves it empty, the browser blocks submission and shows a validation message. Placeholders are just hint text and don’t guarantee a value. Maxlength limits how many characters can be typed, not whether something is present. Pattern restricts the input to match a format, but doesn’t by itself require presence. For safe handling, also validate on the server side. Example: <input type="text" name="username" required>.

The key idea is ensuring a field has a value before the form can be submitted. The attribute that does this is required. It’s a boolean attribute, so simply including it on an input (or textarea, or select) tells the browser that the field must be filled in. If the user leaves it empty, the browser blocks submission and shows a validation message. Placeholders are just hint text and don’t guarantee a value. Maxlength limits how many characters can be typed, not whether something is present. Pattern restricts the input to match a format, but doesn’t by itself require presence. For safe handling, also validate on the server side. Example: .