To set the date value of a date input with JavaScript, we create a date string in YYYY-MM-DD format, then we set the value property of the input to that date string.
For instance, if we have the following date input:
<input type='date'>
Then we write:
const input = document.querySelector('input')
const dt = new Date(2021, 1, 1);
const day = ("0" + dt.getDate()).slice(-2);
const month = ("0" + (dt.getMonth() + 1)).slice(-2);
const date = dt.getFullYear() + "-" + month + "-" + day;
input.value = date
We get the input with document.querySelector .
Then we create the dt date with the Date constructor.
Next, we get the day and month with the getDate and getMonth methods respectively.
And we pad them both with a 0 before it and call slice with -2 to get the last 2 digits.
Next, we create the date string by concatenating the year, which we get from getFullYear , month and day joined together with dashes.
Finally, we set date to input.value .
Now we should see the date input set with the value of the date.
