How to manage forms in Reactjs?

Managing forms in Reactjs usually involves storing form values in component state. Here is a step-by-step guide on how to manage forms:

1. Create a Controlled Component: In Reactjs, form inputs like text can be handled by a controlled component. You can create controlled components by setting the value of the form element to a state variable, and then update that state when changes are made to the form element.

```
class MyForm 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 ( ); } } ```

1. Handle Multiple Inputs: If you have more than one controlled input, you can add a name attribute to each element and let the handler function choose what to do based on the value of event.target.name.

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

1. Validate Form Inputs: You should also validate form inputs, either in your submit handler or right after your inputs change.

1. Use Form Libraries: If you are building complex forms in your React app, you might consider using a form handling library like Formik or React Hook Form. These libraries provide more features like form validation, error messages, form initial values, handling form arrays, etc.

Remember to always update your state with the `setState()` or `useState()` hooks in case of functional components. The state update causes the component to re-render, and the UI is updated with the new state’s value.

Using controlled components in this way makes handling forms in React easy because the form data is being controlled by the React state.