HTML Guide for step
The step attribute is a number that specifies the granularity that the value must adhere to.
It sets the stepping interval when clicking up and down spinner buttons, moving a slider left and right on a range, and validating the different date types.
When used, it must be greater than zero.
Example:
<form>
<!-- Valid values include 1.3, 3.3, 5.3, 7.3, 9.3, 11.3, and so on -->
<input id="myNumber" name="myNumber" type="number" step="2" min="1.3" />
</form>