To set the value of a datetime-local input to a date with JavaScript, we can set the input value to a date string.
For instance, we write:
<input id="dt" type="datetime-local" />
to add the datetime-local input.
Then we write:
const now = new Date();
now.setMinutes(now.getMinutes() - now.getTimezoneOffset());
document.getElementById('dt').value = now.toISOString().slice(0, 16);
We create the now date with the Date constructor.
Then we call setMinutes to change the time to local time by calling it with now.getMinutes() - now.getTimezoneOffset().
Next we set the value of the input with:
document.getElementById('dt').value = now.toISOString().slice(0, 16);
We set the value to a date string by taking the first 16 characters of the date time string with now.toISOString().slice(0, 16).
