181. Which HTML5 feature allows creating a form without server submission?
- a) <form onsubmit="return false">
- b) <form novalidate>
- c) Both a and b
- d) <form method="none">
Answer: A - Returning false in onsubmit prevents submission.
182. Which HTML5 feature allows disabling form validation?
- a) <form novalidate>
- b) <input formnovalidate>
- c) Both a and b
- d) <form validate="false">
Answer: C - novalidate (form-wide) and formnovalidate (per-input) disable validation.
183. Which HTML5 feature allows custom validation messages?
- a) setCustomValidity()
- b) validationMessage property
- c) Both a and b
- d) title attribute
Answer: A - setCustomValidity() overrides default validation messages.
184. Which HTML5 feature allows checking form validity programmatically?
- a) checkValidity()
- b) reportValidity()
- c) Both a and b
- d) validate()
Answer: C - checkValidity() returns boolean, reportValidity() shows UI feedback.
185. Which HTML5 feature allows form autocomplete?
- a) autocomplete attribute
- b) <datalist>
- c) Both a and b
- d) localStorage
Answer: A - The autocomplete attribute controls browser autofill behavior.
186. Which HTML5 feature allows form submission via AJAX?
- a) Fetch API
- b) XMLHttpRequest
- c) Both a and b
- d) <form ajax>
Answer: C - Both Fetch and XHR enable AJAX form submission.
187. Which HTML5 feature allows file uploads with progress tracking?
- a) File API + XHR/Fetch
- b) <input type="file" progress>
- c) Both a and b
- d) WebSocket
Answer: A - File API with XHR/Fetch enables progress events.
188. Which HTML5 feature allows drag-and-drop file uploads?
- a) Drag-and-Drop API
- b) <input type="file" dropzone>
- c) Both a and b
- d) Clipboard API
Answer: A - The Drag-and-Drop API works with file inputs for uploads.
189. Which HTML5 feature allows form data serialization?
- a) FormData API
- b) URLSearchParams
- c) Both a and b
- d) JSON.stringify
Answer: C - FormData for multipart, URLSearchParams for URL-encoded.
190. Which HTML5 feature allows form reset programmatically?
- a) form.reset()
- b) <input type="reset">
- c) Both a and b
- d) location.reload()
Answer: C - Both JS method and reset button clear form values.
191. Which HTML5 feature allows form submission to a new window?
- a) <form target="_blank">
- b) window.open() + form.submit()
- c) Both a and b
- d) <form newwindow>
Answer: A - The target="_blank" attribute opens submissions in a new window.
192. Which HTML5 feature allows form submission to an iframe?
- a) <form target="iframe-name">
- b) <iframe name="...">
- c) Both a and b
- d) postMessage API
Answer: C - Target a named iframe for seamless form responses.
193. Which HTML5 feature allows form data preview before submission?
- a) FormData + JavaScript
- b) <output> element
- c) Both a and b
- d) <preview> element
Answer: C - FormData captures values, <output> displays results.
194. Which HTML5 feature allows form data persistence?
- a) localStorage
- b) sessionStorage
- c) Both a and b
- d) Cookies
Answer: C - Web Storage APIs persist form data client-side.
195. Which HTML5 feature allows form data encryption?
- a) HTTPS
- b) <form encrypt>
- c) Both a and b
- d) Web Crypto API
Answer: A - HTTPS encrypts data during submission (not HTML5-specific).
196. Which HTML5 feature allows form data compression?
- a) gzip (server-side)
- b) <form compress>
- c) Both a and b
- d) Brotli
Answer: A - Compression is handled server-side via HTTP headers.
197. Which HTML5 feature allows form data caching?
- a) Service Workers
- b) localStorage
- c) Both a and b
- d) <form cache>
Answer: C - Service Workers intercept submissions, localStorage stores data.
198. Which HTML5 feature allows form data synchronization?
- a) IndexedDB
- b) WebSocket
- c) Both a and b
- d) <form sync>
Answer: B - WebSockets enable real-time sync with servers.
199. Which HTML5 feature allows form data validation before submission?
- a) Constraint Validation API
- b) JavaScript validation
- c) Both a and b
- d) <form validate>
Answer: C - Native validation (HTML5) and custom JS can be combined.
200. Which HTML5 feature allows form submission without page reload?
- a) Fetch API
- b) XMLHttpRequest
- c) Both a and b
- d) <form reload="false">
Answer: C - Both Fetch and XHR enable seamless AJAX submissions.