Web/API/HTMLInputElement/stepUp

The HTMLInputElement.stepUp() method increments the value of a numeric type of <input> element by the value of the step attribute, or the default step value if the step attribute is not explicitly set. The method, when invoked, increments 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.

Input type	Default step value	Example step declaration
date	`1` (day)	7 day (one week) increments: `<input type="date" min="2019-12-25" step="7">`
month	`1` (month)	12 month (one year) increments: `<input type="month" min="2019-12" step="12">`
week	`1` (week)	Two week increments: `<input type="week" min="2019-W23" step="2">`
time	`60` (seconds)	900 second (15 minute) increments: `<input type="time" min="09:00" step="900">`
datetime-local	`1` (day)	Same day of the week: `<input type="datetime-local" min="019-12-25T19:30" step="7">`
number	`1`	0.1 increments `<input type="number" min="0" step="0.1" max="10">`
range	`1`	Increments by 2: `<input type="range" min="0" step="2" max="10">`

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 on the form control. The default value for the parameter, if no value is passed, is 1. The method will not cause the value to exceed the set max value, or defy the constraints set by the step attribute.

If the value before invoking the stepUp() method is invalid—for example, if it doesn't match the constraints set by the step attribute—invoking the stepUp() 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.

Syntax

element.stepUp( [ stepIncrement ] );

Parameters

stepIncrement: The optional stepIncrement paremeter is a numeric value. If no parameter is passed, stepIncrement defaults to 1.

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="incrementer" min="0" max="25">
  </label>
</p>
<input type="button" value="Increment" id="theButton">

JavaScript

/* make the button call the function */
let button = document.getElementById('theButton')
button.addEventListener('click', function() {
  steponup()
})

function steponup() {
  let input = document.getElementById('theNumber')
  let val = document.getElementById('incrementer').value

  if (val) {  /* increment with a parameter */
    input.stepUp(val)
  } else {    /* or without a parameter. Try it with 0 */
    input.stepUp()
  }
}

CSS

input:invalid {
  border: red solid 3px;
}

Result

Note if you don't pass a parameter to the stepUp method, it defaults to 1. Any other value is a multiplier of the step attribute value, which in this case is 5. If you pass 4 as the stepIncrement, the input will stepUp by 4 * 5, or 20. If the parameter is 0, the number will not be incremented. The stepUp will not allow the input to out of range, in this case stopping when it reaches 400, and rounding down any floats that are passed as a parameter.

Try setting the step increment to 1.2. What happens when you invoke the method?

Try setting the value to 4, which is not valid. What happens when you invoke the method?

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'stepUp()' in that specification.	Living Standard
HTML 5.1The definition of 'stepUp()' in that specification.	Recommendation
HTML5The definition of 'stepUp()' in that specification.	Recommendation	Initial definition

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`stepUp`	Chrome Full support Yes	Edge Full support 12	Firefox Full support 16 Notes' Disabled' Full support 16 Notes' Disabled' Notes' Experimental, and without specific UI. There are still differences with the latest spec: bug 835773. Disabled' From version 16: this feature is behind the `dom.experimental_forms` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	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.