I have a small HTML and JavaScript webpage, and the files will be stored directly on my iPhone. What's the simplest way to open and use the page on the phone, including its JavaScript functionality?
3 Answers
The easiest dependable approach is to serve the page from somewhere and open its URL in Safari. You could publish it with GitHub Pages, use another static host, or run a development server on a computer connected to the same Wi-Fi and visit that computer’s local IP address and port from the iPhone. A progressive web app can also be added to the home screen and cached for offline use.
You can try opening the HTML file from the Files app and previewing it in Safari, but iOS may disable JavaScript for locally opened files. If the page needs JavaScript, hosting it is usually the more reliable option.
If you only have the iPhone, an online coding or hosting service can upload the HTML file and provide a URL. Turning it into a full native app with something like Capacitor is possible, but it’s unnecessary for a simple calculator-style webpage and involves considerably more setup.

The page calculates the missing value in an installment loan when I enter the other three values, so I mainly want something quick that I can use while shopping for a vehicle.