{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"demo4:bug:","articleBody":"```html\r\n\u003ch1\u003e多文件上传  之 xhr formdata\u003c/h1\u003e\r\n    \u003cdiv\u003e\r\n        选择文件(可多选):\r\n        \u003cinput type=\"file\" id=\"f1\" multiple/\u003e\u003cbr/\u003e\u003cbr/\u003e\r\n        \u003cbutton type=\"button\" id=\"btn-submit\"\u003e上 传\u003c/button\u003e\r\n    \u003c/div\u003e\r\n```\r\n```js\r\n  var fileList = document.getElementById('f1').files;\r\n        console.log(document.getElementById('title'))\r\n        if(!fileList.length){\r\n            alert('请选择文件');\r\n            return;\r\n        }\r\n        var fd = new FormData();   //构造FormData对象\r\n        fd.append('title', document.getElementById('title').value); \r\n```\r\n### 关于  `document.getElementById('title')` 不存在直接获取是不是有点问题？","author":{"url":"https://github.com/wangdabaoqq","@type":"Person","name":"wangdabaoqq"},"datePublished":"2019-12-02T10:19:37.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/2/fe-learn-code/issues/2"}