粗浅的理解是把要展现的东西一股脑写道render{}里面就好，然后在页面指定的div内渲染出来。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<script src="./js/react.js"></script>
<script src="./js/react-dom.js"></script>
<script src="./js/browser.min.js"></script>
</head>
<body>
<div id="example"></div>
<script type="text/babel">
var arr = [
<h1 key="1">Hello world!</h1>,
<h2 key="2">React is awesome</h2>,
];
ReactDOM.render(
<div>{arr}</div>,
document.getElementById('example')
)
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<script src="./js/react.js"></script>
<script src="./js/react-dom.js"></script>
<script src="./js/browser.min.js"></script>
</head>
<body>
<div id="example"></div>
<script type="text/babel">
var names = ['andy','bob','kate'];
ReactDOM.render(
<div>
{
names.map(function (name) {
return <div>hello,{name}! </div>
})
}
</div>,
document.getElementById('example')
)
</script>
</body>
</html>
<!-- 顺便复习一下ES6的 Map 结构
var names = ['andy','bob','kate'];
names.map(function(name){
return {name};
}) -->
顺带复习一下es6中map：
es6的Map结构用来表示键值对的集合，和js的Object的区别在于：
object只能用字符串做键名，但是Map是可以包括各类值的 比如
let map = new map{}
map.set(NaN,123);
map.get(+0) // 123