Js 解析Json

get("json/tab.json");

function get(url) {
var xhr = new XMLHttpRequest();
xhr.open("get", url, true);
xhr.onreadystatechange = function() {
if (xhr.readyState == 4 && xhr.status == 200) {
read(xhr.responseText);
}
};
xhr.send(null);
}

function read(json) {
var tab = JSON.parse(json);
console.log(tab.tab[0].tree[0].name);
}

{
"tab": [
{
"name": "人员管理",
"url": "html/page/pm.html",
"tree": [
{
"name": "1a",
"url": "url-a"
}, {
"name": "1b",
"url": "url-b"
}
]
}, {
"name": "资产管理",
"url": "html/page/page_2.html",
"tree": [
{
"name": "1a",
"url": "url-a"
}, {
"name": "1b",
"url": "url-b"
}
]
}
]
}