There are different implementations but, at its base, it often goes:

• The element is assigned event handlers to change the object when the element is edited.
• The object is assigned an array of functions (for each element) that change the element(s).

Thinking in ReactJS way:

import React, {Component} from 'react'; export default MyApp extends Component { constructor(props){ super(props); //Creates a value in state. this.state = {myValue: ''}; }

//Creates a function to effectively changes the value inside your state. 
handleChange(event){
    this.setState({myValue: event.target.value});
}

render() {
    //two way binding: 
    //value={this.state.myValue}
    //onChange={this.handleChange}
    //Receives the value set in your state, and when you change it, inform to change inside the state as well.
    return(
        <input type="text" value={this.state.myValue} onChange={this.handleChange} />
    );
}

}

Holpe helped. =D