点操作符：赋值时只能是已知的值
中括号操作符：赋值时可以是字符串，也可以是变量
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<a id="a" href="http://www.baidu.com" title="跳转"></a>
<input id="ipt" type="text">
<button id="btn">跳转</button>
<script>
window.onload = function () {
var oA = document.getElementById('a');
var oBtn = document.getElementById('btn');
var oIpt = document.getElementById('ipt');
oBtn.onclick = function () {
var list = oIpt.value
console.log(oA.list);
console.log(oA[list]);
}
}
</script>
</body>
</html>
注意：中括号可以代替点操作符