Of all the hats JavaScript can wear, its form-processing features are among the most sought and used. Learn how to use JavaScript for form processing, validation, and more.

Disable JavaScript here to get rid of it in Google Chrome on Android. On the same page, you can tap Add Site Exception, type the URL, and hit Add to allow JavaScript to run on specific websites.

To enable JavaScript, go into the Settings app on your iPhone, click "Safari," then "Advanced," and swipe the JavaScript button to the right so it appears green. Here's a full breakdown with pictures.