<input>
The built-in browser <input>
component lets you render different kinds of form inputs.
<input />
Reference
<input>
To display an input, render the built-in browser <input>
component.
<input name="myInput" />
Props
<input>
supports all common element props.
You can make an input controlled by passing one of these props:
checked
: A boolean. For a checkbox input or a radio button, controls whether it is selected.value
: A string. For a text input, controls its text. (For a radio button, specifies its form data.)
When you pass either of them, you must also pass an onChange
handler that updates the passed value.
These <input>
props are only relevant for uncontrolled inputs:
defaultChecked
: A boolean. Specifies the initial value fortype="checkbox"
andtype="radio"
inputs.defaultValue
: A string. Specifies the initial value for a text input.
These <input>
props are relevant both for uncontrolled and controlled inputs:
accept
: A string. Specifies which filetypes are accepted by atype="file"
input.alt
: A string. Specifies the alternative image text for atype="image"
input.capture
: A string. Specifies the media (microphone, video, or camera) captured by atype="file"
input.autoComplete
: A string. Specifies one of the possible autocomplete behaviors.autoFocus
: A boolean. Iftrue
, React will focus the element on mount.dirname
: A string. Specifies the form field name for the element’s directionality.disabled
: A boolean. Iftrue
, the input will not be interactive and will appear dimmed.children
:<input>
does not accept children.form
: A string. Specifies theid
of the<form>
this input belongs to. If omitted, it’s the closest parent form.formAction
: A string. Overrides the parent<form action>
fortype="submit"
andtype="image"
.formEnctype
: A string. Overrides the parent<form enctype>
fortype="submit"
andtype="image"
.formMethod
: A string. Overrides the parent<form method>
fortype="submit"
andtype="image"
.formNoValidate
: A string. Overrides the parent<form noValidate>
fortype="submit"
andtype="image"
.formTarget
: A string. Overrides the parent<form target>
fortype="submit"
andtype="image"
.height
: A string. Specifies the image height fortype="image"
.list
: A string. Specifies theid
of the<datalist>
with the autocomplete options.max
: A number. Specifies the maximum value of numerical and datetime inputs.maxLength
: A number. Specifies the maximum length of text and other inputs.min
: A number. Specifies the minimum value of numerical and datetime inputs.minLength
: A number. Specifies the minimum length of text and other inputs.multiple
: A boolean. Specifies whether multiple values are allowed for<type="file"
andtype="email"
.name
: A string. Specifies the name for this input that’s submitted with the form.onChange
: AnEvent
handler function. Required for controlled inputs. Fires immediately when the input’s value is changed by the user (for example, it fires on every keystroke). Behaves like the browserinput
event.onChangeCapture
: A version ofonChange
that fires in the capture phase.onInput
: AnEvent
handler function. Fires immediately when the value is changed by the user. For historical reasons, in React it is idiomatic to useonChange
instead which works similarly.onInputCapture
: A version ofonInput
that fires in the capture phase.onInvalid
: AnEvent
handler function. Fires if an input fails validation on form submit. Unlike the built-ininvalid
event, the ReactonInvalid
event bubbles.onInvalidCapture
: A version ofonInvalid
that fires in the capture phase.onSelect
: AnEvent
handler function. Fires after the selection inside the<input>
changes. React extends theonSelect
event to also fire for empty selection and on edits (which may affect the selection).onSelectCapture
: A version ofonSelect
that fires in the capture phase.pattern
: A string. Specifies the pattern that thevalue
must match.placeholder
: A string. Displayed in a dimmed color when the input value is empty.readOnly
: A boolean. Iftrue
, the input is not editable by the user.required
: A boolean. Iftrue
, the value must be provided for the form to submit.size
: A number. Similar to setting width, but the unit depends on the control.src
: A string. Specifies the image source for atype="image"
input.step
: A positive number or an'any'
string. Specifies the distance between valid values.type
: A string. One of the input types.width
: A string. Specifies the image width for atype="image"
input.
Caveats
- Checkboxes need
checked
(ordefaultChecked
), notvalue
(ordefaultValue
). - If a text input receives a string
value
prop, it will be treated as controlled. - If a checkbox or a radio button receives a boolean
checked
prop, it will be treated as controlled. - An input can’t be both controlled and uncontrolled at the same time.
- An input cannot switch between being controlled or uncontrolled over its lifetime.
- Every controlled input needs an
onChange
event handler that synchronously updates its backing value.
Usage
Displaying inputs of different types
To display an input, render an <input>
component. By default, it will be a text input. You can pass type="checkbox"
for a checkbox, type="radio"
for a radio button, or one of the other input types.
export default function MyForm() { return ( <> <label> Text input: <input name="myInput" /> </label> <hr /> <label> Checkbox: <input type="checkbox" name="myCheckbox" /> </label> <hr /> <p> Radio buttons: <label> <input type="radio" name="myRadio" value="option1" /> Option 1 </label> <label> <input type="radio" name="myRadio" value="option2" /> Option 2 </label> <label> <input type="radio" name="myRadio" value="option3" /> Option 3 </label> </p> </> ); }
Providing a label for an input
Typically, you will place every <input>
inside a <label>
tag. This tells the browser that this label is associated with that input. When the user clicks the label, the browser will automatically focus the input. It’s also essential for accessibility: a screen reader will announce the label caption when the user focuses the associated input.
If you can’t nest <input>
into a <label>
, associate them by passing the same ID to <input id>
and <label htmlFor>
. To avoid conflicts between multiple instances of one component, generate such an ID with useId
.
import { useId } from 'react'; export default function Form() { const ageInputId = useId(); return ( <> <label> Your first name: <input name="firstName" /> </label> <hr /> <label htmlFor={ageInputId}>Your age:</label> <input id={ageInputId} name="age" type="number" /> </> ); }
Providing an initial value for an input
You can optionally specify the initial value for any input. Pass it as the defaultValue
string for text inputs. Checkboxes and radio buttons should specify the initial value with the defaultChecked
boolean instead.
export default function MyForm() { return ( <> <label> Text input: <input name="myInput" defaultValue="Some initial value" /> </label> <hr /> <label> Checkbox: <input type="checkbox" name="myCheckbox" defaultChecked={true} /> </label> <hr /> <p> Radio buttons: <label> <input type="radio" name="myRadio" value="option1" /> Option 1 </label> <label> <input type="radio" name="myRadio" value="option2" defaultChecked={true} /> Option 2 </label> <label> <input type="radio" name="myRadio" value="option3" /> Option 3 </label> </p> </> ); }
Reading the input values when submitting a form
Add a <form>
around your inputs with a <button type="submit">
inside. It will call your <form onSubmit>
event handler. By default, the browser will send the form data to the current URL and refresh the page. You can override that behavior by calling e.preventDefault()
. To read the form data, use new FormData(e.target)
.
export default function MyForm() { function handleSubmit(e) { // Prevent the browser from reloading the page e.preventDefault(); // Read the form data const form = e.target; const formData = new FormData(form); // You can pass formData as a fetch body directly: fetch('/some-api', { method: form.method, body: formData }); // Or you can work with it as a plain object: const formJson = Object.fromEntries(formData.entries()); console.log(formJson); } return ( <form method="post" onSubmit={handleSubmit}> <label> Text input: <input name="myInput" defaultValue="Some initial value" /> </label> <hr /> <label> Checkbox: <input type="checkbox" name="myCheckbox" defaultChecked={true} /> </label> <hr /> <p> Radio buttons: <label><input type="radio" name="myRadio" value="option1" /> Option 1</label> <label><input type="radio" name="myRadio" value="option2" defaultChecked={true} /> Option 2</label> <label><input type="radio" name="myRadio" value="option3" /> Option 3</label> </p> <hr /> <button type="reset">Reset form</button> <button type="submit">Submit form</button> </form> ); }
Controlling an input with a state variable
An input like <input />
is uncontrolled. Even if you pass an initial value like <input defaultValue="Initial text" />
, your JSX only specifies the initial value. It does not control what the value should be right now.
To render a controlled input, pass the value
prop to it (or checked
for checkboxes and radios). React will force the input to always have the value
you passed. Typically, you will control an input by declaring a state variable:
function Form() {
const [firstName, setFirstName] = useState(''); // Declare a state variable...
// ...
return (
<input
value={firstName} // ...force the input's value to match the state variable...
onChange={e => setFirstName(e.target.value)} // ... and update the state variable on any edits!
/>
);
}
A controlled input makes sense if you needed state anyway—for example, to re-render your UI on every edit:
function Form() {
const [firstName, setFirstName] = useState('');
return (
<>
<label>
First name:
<input value={firstName} onChange={e => setFirstName(e.target.value)} />
</label>
{firstName !== '' && <p>Your name is {firstName}.</p>}
...
It’s also useful if you want to offer multiple ways to adjust the input state (for example, by clicking a button):
function Form() {
// ...
const [age, setAge] = useState('');
const ageAsNumber = Number(age);
return (
<>
<label>
Age:
<input
value={age}
onChange={e => setAge(e.target.value)}
type="number"
/>
<button onClick={() => setAge(ageAsNumber + 10)}>
Add 10 years
</button>
The value
you pass to controlled components should not be undefined
or null
. If you need the initial value to be empty (such as with the firstName
field below), initialize your state variable to an empty string (''
).
import { useState } from 'react'; export default function Form() { const [firstName, setFirstName] = useState(''); const [age, setAge] = useState('20'); const ageAsNumber = Number(age); return ( <> <label> First name: <input value={firstName} onChange={e => setFirstName(e.target.value)} /> </label> <label> Age: <input value={age} onChange={e => setAge(e.target.value)} type="number" /> <button onClick={() => setAge(ageAsNumber + 10)}> Add 10 years </button> </label> {firstName !== '' && <p>Your name is {firstName}.</p> } {ageAsNumber > 0 && <p>Your age is {ageAsNumber}.</p> } </> ); }
Optimizing re-rendering on every keystroke
When you use a controlled input, you set the state on every keystroke. If the component containing your state re-renders a large tree, this can get slow. There’s a few ways you can optimize re-rendering performance.
For example, suppose you start with a form that re-renders all page content on every keystroke:
function App() {
const [firstName, setFirstName] = useState('');
return (
<>
<form>
<input value={firstName} onChange={e => setFirstName(e.target.value)} />
</form>
<PageContent />
</>
);
}
Since <PageContent />
doesn’t rely on the input state, you can move the input state into its own component:
function App() {
return (
<>
<SignupForm />
<PageContent />
</>
);
}
function SignupForm() {
const [firstName, setFirstName] = useState('');
return (
<form>
<input value={firstName} onChange={e => setFirstName(e.target.value)} />
</form>
);
}
This significantly improves performance because now only SignupForm
re-renders on every keystroke.
If there is no way to avoid re-rendering (for example, if PageContent
depends on the search input’s value), useDeferredValue
lets you keep the controlled input responsive even in the middle of a large re-render.
Troubleshooting
My text input doesn’t update when I type into it
If you render an input with value
but no onChange
, you will see an error in the console:
// 🔴 Bug: controlled text input with no onChange handler
<input value={something} />
value
prop to a form field without an onChange
handler. This will render a read-only field. If the field should be mutable use defaultValue
. Otherwise, set either onChange
or readOnly
.As the error message suggests, if you only wanted to specify the initial value, pass defaultValue
instead:
// ✅ Good: uncontrolled input with an initial value
<input defaultValue={something} />
If you want to control this input with a state variable, specify an onChange
handler:
// ✅ Good: controlled input with onChange
<input value={something} onChange={e => setSomething(e.target.value)} />
If the value is intentionally read-only, add a readOnly
prop to suppress the error:
// ✅ Good: readonly controlled input without on change
<input value={something} readOnly={true} />
My checkbox doesn’t update when I click on it
If you render a checkbox with checked
but no onChange
, you will see an error in the console:
// 🔴 Bug: controlled checkbox with no onChange handler
<input type="checkbox" checked={something} />
checked
prop to a form field without an onChange
handler. This will render a read-only field. If the field should be mutable use defaultChecked
. Otherwise, set either onChange
or readOnly
.As the error message suggests, if you only wanted to specify the initial value, pass defaultChecked
instead:
// ✅ Good: uncontrolled checkbox with an initial value
<input type="checkbox" defaultChecked={something} />
If you want to control this checkbox with a state variable, specify an onChange
handler:
// ✅ Good: controlled checkbox with onChange
<input type="checkbox" checked={something} onChange={e => setSomething(e.target.checked)} />
If the checkbox is intentionally read-only, add a readOnly
prop to suppress the error:
// ✅ Good: readonly controlled input without on change
<input type="checkbox" checked={something} readOnly={true} />
My input caret jumps to the beginning on every keystroke
If you control an input, you must update its state variable to the input’s value from the DOM during onChange
.
You can’t update it to something other than e.target.value
(or e.target.checked
for checkboxes):
function handleChange(e) {
// 🔴 Bug: updating an input to something other than e.target.value
setFirstName(e.target.value.toUpperCase());
}
You also can’t update it asynchronously:
function handleChange(e) {
// 🔴 Bug: updating an input asynchronously
setTimeout(() => {
setFirstName(e.target.value);
}, 100);
}
To fix your code, update it synchronously to e.target.value
:
function handleChange(e) {
// ✅ Updating a controlled input to e.target.value synchronously
setFirstName(e.target.value);
}
If this doesn’t fix the problem, it’s possible that the input gets removed and re-added from the DOM on every keystroke. This can happen if you’re accidentally resetting state on every re-render. For example, this can happen if the input or one of its parents always receives a different key
attribute, or if you nest component definitions (which is not allowed in React and causes the “inner” component to always be considered a different tree).
I’m getting an error: “A component is changing an uncontrolled input to be controlled”
If you provide a value
to the component, it must remain a string throughout its lifetime.
You cannot pass value={undefined}
first and later pass value="some string"
because React won’t know whether you want the component to be uncontrolled or controlled. A controlled component should always receive a string value
, not null
or undefined
.
If your value
is coming from an API or a state variable, it might be initialized to null
or undefined
. In that case, either set it to an empty string (''
) initially, or pass value={someValue ?? ''}
to ensure value
is a string.
Similarly, if you pass checked
to a checkbox, ensure it’s always a boolean.