The HTMLInputElement.stepDown([n])
method decrements the value of a numeric type of <input>
element by the value of the step
attribute or up to n
multiples of the step attribute if a number is passed as the parameter. The method, when invoked, decrements the value
by (step
* n), where n defaults to 1 if not specified, and step
defaults to the default value for step
if not specified.
Valid on all numeric, date, and time input types that support the step attribute, includingdate, month, week, time, datetime-local, number, and range.
Given <input id="myTime" type="time" max="17:00" step="900" value="17:00">
, invoking myTime.step(3)
will change the value to 16:15, decrementing the time by 3 * 900
, or 45 minutes. myTime.step()
, with no parameter, would have resulted in 16:45
, as n
defaults to 1
.
<!-- decrements by intervals of 900 seconds (15 minute) --><input type="time" max="17:00" step="900">
<!-- decrements by intervals of 7 days (one week) --><input type="date" max="2019-12-25" step="7">
<!-- decrements by intervals of 12 months (one year) --><input type="month" max="2019-12" step="12">
The method, when invoked, changes the form control's value by the value given in the step
attribute, multiplied by the parameter, within the constraints set within the form control. The default value for the parameter, if not is passed, is 1. The method will not cause the value to go below the min
value set or defy the constraints set by the step
attribute. A negative value for n
will increment the value, but will not increment beyond the max
value.
If the value before invoking the stepDown()
method is invalid, for example, if it doesn't match the constraints set by the step
attribute, invoking the stepDown()
method will return a value that does match the form controls constraints.
If the form control is non time, date, or numeric in nature, and therefore does not support the step
attribute (see the list of supported input types in the the table above), or if the step
value is set to any
, an InvalidStateError
exception is thrown.
HTMLInputElement.stepDown()
- Decrements the
value
by (step
* n), where n defaults to 1 if not specified. Throws an INVALID_STATE_ERR exception:
Syntax
element.stepDown( [ stepDecrement ] );
Parameters
stepDecrement
- The optional
stepDecrement
paremeter is a numeric value. If no parameter is passed, stepDecrement defaults to 1. - If the value is a float, the value will increment as if
Math.floor(stepDecrement)
was passed. If the value is negative, the value will be incremented instead of decremented.
Example
Click the button in this example to increment the number input type:
HTML
<p> <label>Enter a number between 0 and 400 that is divisible by 5: <input type="number" step="5" id="theNumber" min="0" max="400"> </label> </p> <p> <label>Enter how many values of step you would like to increment by or leave it blank: <input type="number" step="1" id="decrementer" min="-2" max="15"> </label> </p> <input type="button" value="Decrement" id="theButton">
JavaScript
/* make the button call the function */ let button = document.getElementById('theButton'); button.addEventListener('click', function() { stepondown();} ); function stepondown() { let input = document.getElementById('theNumber'); let val = document.getElementById('decrementer').value; if (val) { /* increment with a parameter */ input.stepDown(val); } else { /* or without a parameter. Try it with 0, 5, -2, etc. */ input.stepDown(); } }
CSS
input:invalid { border: red solid 3px; }
Result
Note if you don't pass a parameter to the stepDown()
method, it defaults to 1. Any other value is a multiplier of the step
attribute value, which in this case is 5. If we pass 4 as the stepDecrement, the input will stepDown by 4 * 5
, or 20
. If the parameter is 0, the number will not be decremented. The stepDown() method will not allow the input to go out of range, in this case stopping when it reaches 0 and rounding down and floats that are passed as a parameter.
Try setting the step decrementer to 1.2
. What happens when you invoke the method?
Try setting the value to 44
, which is not valid. What happens when you invoke the method?
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'stepDown()' in that specification. |
Living Standard | |
HTML 5.1 The definition of 'stepDown()' in that specification. |
Recommendation | |
HTML5 The definition of 'stepDown()' in that specification. |
Recommendation | Initial definition |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
stepDown | Chrome Full support Yes | Edge Full support 12 | Firefox
Full support
16
| IE ? | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
- Compatibility unknown
- Compatibility unknown
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.
See also
<input>
HTMLInputElement
HTMLInputElement.stepUp()
step
,min
andmax
attributes