JAVASCRIPT

react text input onchange

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>
    );
  }
}

react input text onchange target method

class App extends React.Component {
  constructor(props) {
    super(props);
    
    this.state = {
      data: 'Bound data...'
    }
    this.updateState = this.updateState.bind(this);
    
  };
  updateState(e) {
    this.setState({data: e.target.value});
  }
  render() {
    return (
    <>
        <input type="text" value = {this.state.data} onChange = {this.updateState} />
        <h4>{this.state.data}</h4>
        </>
             );
  }
}
        ReactDOM.render(
        <App />, document.getElementById('mountNode') );

onChange in react js

import React from "react";

function App() {
  function handleChange(event) {
    console.log(event.target.value);
  }

  return (
    <input
      type="text"
      name="firstName"
      onChange={handleChange}
    />
  );
}

export default App;