Normally, when you click on a HTML input element, it allows you to select any hour and minute (6:01, 6:02, etc.). But I want to add a time input element that only allows you to select times along 15-minute intervals (6:00, 6:15, 6:30, etc.) to the page I'm working on.
The documentation says that you can use the "step" attribute on the element to tell it the number of seconds between each of the selectable time increments. 15 minutes is 900 seconds, so I tried:
<input type="time" step="900">
but that appeared to be no different from when the "step" attribute was not used.