HTML attribute: step
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The step
attribute is a number that specifies the granularity that the value must adhere to or the keyword any
. It is valid for the numeric input types, including the date, month, week, time, datetime-local, number and range types.
The step
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. If not explicitly included, step
defaults to 1 for number
and range
, and 1 unit type (minute, week, month, day) for the date/time input types. The value must be a positive number - integer or float — or the special value any
, which means no stepping is implied and any value is allowed (barring other constraints, such as min
and max
).
Only values which are a whole number of steps from the step base are valid. The step base is min
if specified, value
otherwise, or 0
if neither is provided (except for week
, which has a default step base of −259,200,000, representing the start of week 1970-W01
).
Syntax
Input type | Value | Example |
---|---|---|
date | 1 (day) | <input type="date" min="2019-12-25" step="1"> |
month | 1 (month) | <input type="month" min="2019-12" step="12"> |
week | 1 (week) | <input type="week" min="2019-W23" step="2"> |
time | 60 (seconds) | <input type="time" min="09:00" step="900"> |
datetime-local | 60 (seconds) |
<input type="datetime-local" min="2019-12-25T19:30"
step="900">
|
number | 1 |
<input type="number" min="0" step="0.1" max="10">
|
range | 1 | <input type="range" min="0" step="2" max="10"> |
If any
is not explicitly set, valid values for the number
, date/time input types, and range
input types are equal to the basis for stepping - the min
value and increments of the step value, up to the max
value, if specified. The following example results in any even integer, 10 or greater, being valid:
<input type="number" min="10" step="2" />
If step
is omitted, any integer is valid but floats like 4.2 are not valid as step
defaults to 1. For 4.2 to be valid:
- either
step
would have to be set toany
, 0.1, or 0.2, - or the
min
value would have to be a number ending in .2, such as 0.2, 1.2, or -5.2.
Examples
min
impact on step
The value of min
defines valid values, even if the step
attribute is not included. This is because step
defaults to 1
for the number
input type.
In this example, we add a big red border around invalid inputs:
input:invalid {
border: solid red 3px;
}
We then define an input with a minimum value of 1.2 and a step value of 2:
<input id="myNumber" name="myNumber" type="number" step="2" min="1.2" />
Valid values include 1.2, 3.2, 5.2, 7.2, 9.2, 11.2, and so on. Only floats with an odd-numbered integer part and a decimal part of .2 are valid. The number spinner, if present, generates valid float values of 1.2 and greater, in increments of 2.
Note:
When the data entered by the user doesn't adhere to the stepping configuration, the value is considered invalid in constraint validation and will match the :invalid
and :out-of-range
pseudoclasses.
See Client-side validation and stepMismatch
for more information.
Accessibility concerns
Provide instructions to help users understand how to complete the form and use individual form controls. Indicate any required and optional input, data formats, and other relevant information. When using the min
attribute, ensure this minimum requirement is understood by the user. Providing instructions within the <label>
may be sufficient. If providing instructions outside of labels, which allows more flexible positioning and design, consider using aria-labelledby
or aria-describedby
.
Specifications
Specification |
---|
HTML # attr-input-step |
Browser compatibility
See also
max
min
- Constraint validation
- Form validation
validityState.stepMismatch
:out-of-range
<input>
- date, month, week, time, datetime-local, number and range types, and the
<meter>