如何在react里嵌入iframe?

无法访问iframe地址

index.js文件

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

ReactDOM.render(<App />, document.getElementById('root'));

App.js

import React from 'react'

class App extends React.Component {
    render() {
        return (
            <div>
                <h1>Outside iFrame</h1>
                <iframe title="myiframe" src="./target.html" width="600px" height="400px"></iframe>
            </div>
        )
    }
}

export default App

target.html

<html>

<head></head>

<body>
    <h1>Inside IFrame</h1>
</body>

</html>

index.html

<div ></div>

为什么引入的是

<iframe title="myiframe" src="./target.html" width="600px" height="400px"></iframe>