Get form data in React

There are a few ways to do this:

1) Get values from array of form elements by index

handleSubmit = (event) => {
  event.preventDefault();
  console.log(event.target[0].value)
}

2) Using name attribute in html

handleSubmit = (event) => {
  event.preventDefault();
  console.log(event.target.elements.username.value) // from elements property
  console.log(event.target.username.value)          // or directly
}

<input type="text" name="username"/>

3) Using refs

handleSubmit = (event) => {
  console.log(this.inputNode.value)
}

<input type="text" name="username" ref={node => (this.inputNode = node)}/>

Full example

class NameForm extends React.Component {
  handleSubmit = (event) => {
    event.preventDefault()
    console.log(event.target[0].value)
    console.log(event.target.elements.username.value)
    console.log(event.target.username.value)
    console.log(this.inputNode.value)
  }
  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Name:
          <input
            type="text"
            name="username"
            ref={node => (this.inputNode = node)}
          />
        </label>
        <button type="submit">Submit</button>
      </form>
    )
  }
}

For those who don't want to use ref and reset the state with OnChange event, you can just use simple OnSubmit handle and loop through the FormData object.

Note that you cannot access formData.entries() directly since it is an iterable, you have to loop over it.

This example is using React Hooks:

const LoginPage = () => {
  const handleSubmit = (event) => {
    const formData = new FormData(event.currentTarget);
    event.preventDefault();
    for (let [key, value] of formData.entries()) {
      console.log(key, value);
    }
  };

  return (
    <div>
      <form onSubmit={handleSubmit}>
        <input type="text" name="username" placeholder="Email" />
        <input type="password" name="password" placeholder="Password" />
        <button type="submit">Login</button>
      </form>
    </div>
  );
};

And if you're using TypeScript:

export const LoginPage: React.FC<{}> = () => {
  const handleSubmit: React.FormEventHandler<HTMLFormElement> = (event) => {
    const formData = new FormData(event.currentTarget);
    event.preventDefault();
    for (let [key, value] of formData.entries()) {
      console.log(key, value);
    }
  };

  return (
    <div>
      <form onSubmit={handleSubmit}>
        <input type="text" name="username" placeholder="Email" />
        <input type="password" name="password" placeholder="Password" />
        <button type="submit">Login</button>
      </form>
    </div>
  );
};

Adding on to Michael Schock's answer:

class MyForm extends React.Component {
  constructor() {
    super();
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleSubmit(event) {
    event.preventDefault();
    const data = new FormData(event.target);

    console.log(data.get('email')); // Reference by form input's `name` tag

    fetch('/api/form-submit-url', {
      method: 'POST',
      body: data,
    });
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label htmlFor="username">Enter username</label>
        <input id="username" name="username" type="text" />

        <label htmlFor="email">Enter your email</label>
        <input id="email" name="email" type="email" />

        <label htmlFor="birthdate">Enter your birth date</label>
        <input id="birthdate" name="birthdate" type="text" />

        <button>Send data!</button>
      </form>
    );
  }
}

See this Medium article: How to Handle Forms with Just React

This method gets form data only when the Submit button is pressed. It is much cleaner, IMO!

There isn't any need to use refs. You can access it using an event:

function handleSubmit(e) {
    e.preventDefault()
    const {username, password } = e.target.elements
    console.log({username: username.value, password: password.value })
}

<form onSubmit={handleSubmit}>
   <input type="text" id="username"/>
   <input type="text" id="password"/>
   <input type="submit" value="Login" />
</form>

An alternative approach is to use the ref attribute and reference the values with this.refs. Here is a simple example:

render: function() {
    return (<form onSubmit={this.submitForm}>
        <input ref="theInput" />
    </form>);
},
submitForm: function(e) {
    e.preventDefault();
    alert(React.findDOMNode(this.refs.theInput).value);
}

More info can be found in the React docs: https://facebook.github.io/react/docs/more-about-refs.html#the-ref-string-attribute

For a lot of the reasons described in How do I use radio buttons in React? this approach isn't always the best, but it does present a useful alternative in some simple cases.

An easy way to deal with refs:

class UserInfo extends React.Component {

  constructor(props) {
    super(props);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleSubmit(e) {
    e.preventDefault();

    const formData = {};
    for (const field in this.refs) {
      formData[field] = this.refs[field].value;
    }
    console.log('-->', formData);
  }

  render() {
    return (
        <div>
          <form onSubmit={this.handleSubmit}>
            <input ref="phone" className="phone" type='tel' name="phone"/>
            <input ref="email" className="email" type='tel' name="email"/>
            <input type="submit" value="Submit"/>
          </form>
        </div>
    );
  }
}

export default UserInfo;

You could switch the onClick event handler on the button to an onSubmit handler on the form:

render : function() {
      return (
        <form onSubmit={this.handleLogin}>
          <input type="text" name="email" placeholder="Email" />
          <input type="password" name="password" placeholder="Password" />
          <button type="submit">Login</button>
        </form>
      );
    },

Then you can make use of FormData to parse the form (and construct a JSON object from its entries if you want).

handleLogin: function(e) {
   const formData = new FormData(e.target)
   const user = {}

   e.preventDefault()

   for (let entry of formData.entries()) {
       user[entry[0]] = entry[1]
   }

   // Do what you will with the user object here
}

If all your inputs / textarea have a name, then you can filter all from event.target:

onSubmit(event){
  const fields = Array.prototype.slice.call(event.target)
      .filter(el => el.name)
      .reduce((form, el) => ({
        ...form,
        [el.name]: el.value,
      }), {})
}

Totally uncontrolled form 😊 without onChange methods, value, defaultValue...

Here is the shortest way to get data from the form and the best way to avoid id and ref just by using FormData:

import React, { Component } from 'react'

class FormComponent extends Component {
  formSubmit = (event) => {
    event.preventDefault()
    var data = new FormData(event.target)
    let formObject = Object.fromEntries(data.entries())
    console.log(formObject)
  }
  render() {
    return (
      <div>
        <form onSubmit={this.formSubmit}>
          <label>Name</label>
          <input name="name" placeholder="name" />
          <label>Email</label>
          <input type="email" name="email" />
          <input type="submit" />
        </form>
      </div>
    )
  }
}
export default FormComponent

I would suggest the following approach:

import {Autobind} from 'es-decorators';

export class Form extends Component {

    @Autobind
    handleChange(e) {
        this.setState({[e.target.name]: e.target.value});
    }

    @Autobind
    add(e) {
        e.preventDefault();
        this.collection.add(this.state);
        this.refs.form.reset();
    }

    shouldComponentUpdate() {
        return false;
    }

    render() {
        return (
            <form onSubmit={this.add} ref="form">
                <input type="text" name="desination" onChange={this.handleChange}/>
                <input type="date" name="startDate" onChange={this.handleChange}/>
                <input type="date" name="endDate" onChange={this.handleChange}/>
                <textarea name="description" onChange={this.handleChange}/>
                <button type="submit">Add</button>
            </form>
        )
    }

}

For TypeScript users

import react from 'react'

interface FormInterface {
    [key: string]: string
}

const handleSubmit = (event: React.FormEvent<HTMLFormElement>) => {
   event.preventDefault();
   let formData = new FormData(event.currentTarget)
   let formObj: FormInterface = {}
   for (let [key, value] of Array.from(formData.entries())) {
     formObj[key] = value.toString()
   }
};

<form onSubmit={handleSubmit}>
   <input type="text" name="email" placeholder="Email" />
   <input type="password" name="password" placeholder="Password" />
   <button type="submit">Login</button>
</form>

Shortest way:

onSubmit={(event) => {
  event.preventDefault();
  const formData = new FormData(event.currentTarget);
  const formEntries = Object.fromEntries(formData.entries());
  console.log(formEntries);
}}

More clear example with es6 destructing

class Form extends Component {
    constructor(props) {
        super(props);
        this.state = {
            login: null,
            password: null,
            email: null
        }
    }

    onChange(e) {
        this.setState({
            [e.target.name]: e.target.value
        })
    }

    onSubmit(e) {
        e.preventDefault();
        let login = this.state.login;
        let password = this.state.password;
        // etc
    }

    render() {
        return (
            <form onSubmit={this.onSubmit.bind(this)}>
                <input type="text" name="login" onChange={this.onChange.bind(this)} />
                <input type="password" name="password" onChange={this.onChange.bind(this)} />
                <input type="email" name="email" onChange={this.onChange.bind(this)} />
                <button type="submit">Sign Up</button>
            </form>
        );
    }
}

The simplest solution that came to my mind is this:

<form onSubmit={(e) => handleLogin(e)}>
    <input type="text" name="email" placeholder="Email" />
    <input type="password" name="password" placeholder="Password" />
    <button type="submit">Login</button>
</form>

Your handle fuction:

const handleLogin = (e) => {
    e.preventDefault()
    const data = {
        email: e.target.elements.email.value,
        password: e.target.elements.password.value
    }
    console.log('FormData: ', data)
}

When you click on your login button you will see FormData in console in this format: FormData: {email: 'whatever you tiped here', password: 'also whatever you tiped here'}.

e.target.elements.email.value targets elements with specific name, in your case it is email and password.

After console.log in handleLogin, you can do some verification logic and login logic.

TypeScript will complain if you try Aliaksandr Sushkevich's solution. One workaround can be done using type assertions:

<form
    onSubmit={(e: React.SyntheticEvent) => {
      e.preventDefault();
      const target = e.target as typeof e.target & {
        username: { value: string };
        password: { value: string };
      };
      const username = target.username.value; // typechecks
      const password = target.password.value; // typechecks
      // etc...
    }}
>
<input type="text" name="username"/>
...

Though, this is still just a workaround, because here you are telling TypeScript what to expect. This will break at runtime if you add a value that doesn't have a corresponding input element.

Give your inputs ref like this

<input type="text" name="email" placeholder="Email" ref="email" />
<input type="password" name="password" placeholder="Password" ref="password" />

Then you can access it in your handleLogin like so:

handleLogin: function(e) {
   e.preventDefault();
    console.log(this.refs.email.value)
    console.log(this.refs.password.value)
}

I use like this using React Component state:

<input type="text" name='value' value={this.state.value} onChange={(e) => this.handleChange(e)} />

handleChange(e){
   this.setState({[e.target.name]: e.target.value})
}`

Also, this can be used too.

handleChange: function(state,e) {
  this.setState({[state]: e.target.value});
},
render : function() {
  return (
    <form>
      <input type="text" name="email" placeholder="Email" value={this.state.email} onChange={this.handleChange.bind(this, 'email')} />
      <input type="password" name="password" placeholder="Password" value={this.state.password} onChange={this.handleChange.bind(this, 'password')}/>
      <button type="button" onClick={this.handleLogin}>Login</button>
    </form>
  );
},
handleLogin: function() {
  console.log("EMail: ", this.state.email);
  console.log("Password: ", this.state.password);
}

If you are using Redux in your project, you can consider using the higher order component redux-form.

In many events in JavaScript, we have event which gives an object, including what event happened and what are the values, etc.

That's what we use with forms in React as well.

So in your code you set the state to the new value. Something like this:

class UserInfo extends React.Component {

  constructor(props) {
    super(props);
    this.handleLogin = this.handleLogin.bind(this);
  }

  handleLogin(e) {
    e.preventDefault();
    for (const field in this.refs) {
      this.setState({this.refs[field]: this.refs[field].value});
    }
  }

  render() {
    return (
        <div>
          <form onSubmit={this.handleLogin}>
            <input ref="email" type="text" name="email" placeholder="Email" />
            <input ref="password" type="password" name="password" placeholder="Password" />
            <button type="button">Login</button>
          </form>
        </div>
    );
  }
}

export default UserInfo;

Also this is the form example in React v.16, just as reference for the form you creating in the future:

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};

    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleChange(event) {
    this.setState({value: event.target.value});
  }

  handleSubmit(event) {
    alert('A name was submitted: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Name:
          <input type="text" value={this.state.value} onChange={this.handleChange} />
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

To improve the user experience; when the user clicks on the submit button, you can try to get the form to first show a sending message. Once we've received a response from the server, it can update the message accordingly. We achieve this in React by chaining statuses. See codepen or snippets below:

The following method makes the first state change:

handleSubmit(e) {
    e.preventDefault();
    this.setState({ message: 'Sending...' }, this.sendFormData);
}

As soon as React shows the above Sending message on screen, it will call the method that will send the form data to the server: this.sendFormData(). For simplicity I've added a setTimeout to mimic this.

sendFormData() {
  var formData = {
      Title: this.refs.Title.value,
      Author: this.refs.Author.value,
      Genre: this.refs.Genre.value,
      YearReleased: this.refs.YearReleased.value};
  setTimeout(() => { 
    console.log(formData);
    this.setState({ message: 'data sent!' });
  }, 3000);
}

In React, the method this.setState() renders a component with new properties. So you can also add some logic in render() method of the form component that will behave differently depending on the type of response we get from the server. For instance:

render() {
  if (this.state.responseType) {
      var classString = 'alert alert-' + this.state.type;
      var status = <div id="status" className={classString} ref="status">
                     {this.state.message}
                   </div>;
  }
return ( ...

codepen

 onChange(event){
     console.log(event.target.value);
  }
  handleSubmit(event){ 
    event.preventDefault();
    const formData = {};
      for (const data in this.refs) {
        formData[data] = this.refs[data].value;
      }
    console.log(formData);
  }



 <form onSubmit={this.handleSubmit.bind(this)}>
  <input type="text" ref="username" onChange={this.onChange} className="form-control"/>
  <input type="text" ref="password" onChange={this.onChange} className="form-control"/>
  <button type="submit" className="btn-danger btn-sm">Search</button>
 </form>

Output image attached here

This might help Meteor (v1.3) users:

render: function() {
    return (
        <form onSubmit={this.submitForm.bind(this)}>
            <input type="text" ref="email" placeholder="Email" />
            <input type="password" ref="password" placeholder="Password" />
            <button type="submit">Login</button>
        </form>
    );
},
submitForm: function(e) {
    e.preventDefault();
    console.log( this.refs.email.value );
    console.log( this.refs.password.value );
}

This is an example of dynamically added fields. Here form data will store by input name key using a React useState hook.

import React, { useState } from 'react'

function AuthForm({ firebase }) {
    const [formData, setFormData] = useState({});

    // On Form Submit
    const onFormSubmit = (event) => {
        event.preventDefault();
        console.log('data', formData)
        // Submit here
    };

    // get Data
    const getData = (key) => {
        return formData.hasOwnProperty(key) ? formData[key] : '';
    };

    // Set data
    const setData = (key, value) => {
        return setFormData({ ...formData, [key]: value });
    };

    console.log('firebase', firebase)
    return (
        <div className="wpcwv-authPage">
            <form onSubmit={onFormSubmit} className="wpcwv-authForm">
                <input name="name" type="text" className="wpcwv-input" placeholder="Your Name" value={getData('name')} onChange={(e) => setData('name', e.target.value)} />
                <input name="email" type="email" className="wpcwv-input" placeholder="Your Email" value={getData('email')} onChange={(e) => setData('email', e.target.value)} />
                <button type="submit" className="wpcwv-button wpcwv-buttonPrimary">Submit</button>
            </form>
        </div>
    )
}

export default AuthForm

For the people living in the future,

Looks like it took some time for React to provide a proper answer to this with React 19 <form> component. Be careful that this is a Canary release and not production ready yet.

To quote the example in the docs verbatim:

export default function Search() {
  function search(formData) {
    const query = formData.get("query");
    alert(`You searched for '${query}'`);
  }
  return (
    <form action={search}>
      <input name="query" />
      <button type="submit">Search</button>
    </form>
  );
}

Now it's pretty straightforward to access form fields. But be aware of a few things:

• Previously, form action was a string such as "/submit" which was the path of the page to GET, or POST if form method="POST".
• If you want to do multiple things with different buttons, you can also attach actions to <button>s like so:

  <button formAction={save}>Save draft</button>
  

• See also: useActionState, useFormStatus

If you have multiple occurrences of an element name, then you have to use forEach().

HTML

  <input type="checkbox" name="delete" id="flizzit" />
  <input type="checkbox" name="delete" id="floo" />
  <input type="checkbox" name="delete" id="flum" />
  <input type="submit" value="Save"  onClick={evt => saveAction(evt)}></input>

JavaScript

const submitAction = (evt) => {
  evt.preventDefault();
  const dels = evt.target.parentElement.delete;
  const deleted = [];
  dels.forEach((d) => { if (d.checked) deleted.push(d.id); });
  window.alert(deleted.length);
};

Note the dels in this case is a RadioNodeList, not an array, and is not an Iterable. The forEach() is a built-in method of the list class. You will not be able to use a map() or reduce() here.

<form onSubmit={handleLogin}>
    <input type="text" name="email" placeholder="Email" />
    <input type="text" name="password" placeholder="Password" />
    <button type="submit">Login</button>
</form>

const handleLogin = (event) => {
    event.preventDefault();
    console.log(event.target[0].value)
    console.log(event.target[1].value)
}

const HandleSubmit = (e) => {
    e.preventDefault();
    let formData = e.target[0].form;
        axios({
            url: 'http://localhost:4000/data/add',
            method: 'POST',
            data: new FormData(formData)
        }).then(async (data) => {
            await toastr.success('Added Successfully', {
                timeOut: 1000,
            });
            await setTimeout(() => {
                window.location.reload();
            }, 1000)

        })
    }

I think this is also the answer that you need. In addition, Here I add the required attributes. onChange attributes of Each input components are functions. You need to add your own logic there.

handleEmailChange: function(e) {
    this.setState({email: e.target.value});
},
handlePasswordChange: function(e) {
   this.setState({password: e.target.value});
},
formSubmit : async function(e) {
    e.preventDefault();
    // Form submit Logic
  },
render : function() {
      return (
        <form onSubmit={(e) => this.formSubmit(e)}>
          <input type="text" name="email" placeholder="Email" value={this.state.email} onChange={this.handleEmailChange} required />
          <input type="password" name="password" placeholder="Password" value={this.state.password} onChange={this.handlePasswordChange} required />
          <button type="button">Login</button>
        </form>);
},
handleLogin: function() {
    //Login Function
}