---
# System prepended metadata

title: React Js

---

# React Js

<ClassName prop>

Ex: <Square value=3> is a Square class initiated with its `value` property =3.

Class is created via

```
class Square extends React.Component {
  renderSquare(i) {
    return <Square value={i} />;
  }
  
  render(){
     
     return(
     
      html element
     )
  }
}
```

React class definition always ends with render() to render 

To initate an instance:

```
ReactDOM.render(
  <ClassName />,
  document.getElementById(...)
)

```