属性值有以下几个比较常用：
accept：表示可以选择的文件MIME类型，多个MIME类型用英文逗号分开，常用的MIME类型见下表。
multiple：是否可以选择多个文件，多个文件时其value值为第一个文件的虚拟路径。
1、accept
只能选择png和gif图片
1
| <input id="fileId1" type="file" accept="image/png,image/gif" name="file" />
|
2、multiple
多文件上传
1
| <input id="fileId2" type="file" multiple="multiple" name="file" />
|
3、常用MIME类型
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
| 后缀名 MIME名称
*.3gpp audio/3gpp, video/3gpp
*.ac3 audio/ac3
*.asf allpication/vnd.ms-asf
*.au audio/basic
*.css text/css
*.csv text/csv
*.doc application/msword
*.dot application/msword
*.dtd application/xml-dtd
*.dwg image/vnd.dwg
*.dxf image/vnd.dxf
*.gif image/gif
*.htm text/html
*.html text/html
*.jp2 image/jp2
*.jpe image/jpeg
*.jpeg image/jpeg
*.jpg image/jpeg
*.js text/javascript, application/javascript
*.json application/json
*.mp2 audio/mpeg, video/mpeg
*.mp3 audio/mpeg
*.mp4 audio/mp4, video/mp4
*.mpeg video/mpeg
*.mpg video/mpeg
*.mpp application/vnd.ms-project
*.ogg application/ogg, audio/ogg
*.pdf application/pdf
*.png image/png
*.pot application/vnd.ms-powerpoint
*.pps application/vnd.ms-powerpoint
*.ppt application/vnd.ms-powerpoint
*.rtf application/rtf, text/rtf
*.svf image/vnd.svf
*.tif image/tiff
*.tiff image/tiff
*.txt text/plain
*.wdb application/vnd.ms-works
*.wps application/vnd.ms-works
*.xhtml application/xhtml+xml
*.xlc application/vnd.ms-excel
*.xlm application/vnd.ms-excel
*.xls application/vnd.ms-excel
*.xlt application/vnd.ms-excel
*.xlw application/vnd.ms-excel
*.xml text/xml, application/xml
*.zip aplication/zip
*.xlsx application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
|
二、AJAX上传文件
在说到ajax上传文件。ajax上传的时候，需要获得input:file选择的文件（可能为多个文件），获取其文件列表为：
1
2
3
|
document.querySelector("#fileId").files
|
获得的文件列表，然后遍历插入到表单数据当中。即：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
var oFiles = document.querySelector("#fileId");
var formData = new FormData();
for (var i = 0, file; file = oFiles[i]; i++) {
formData.append(file.name, file);
}
|
获得表单数据之后，就可以用ajax的POST上传。
1
2
3
4
5
6
7
8
9
| // 实例化一个AJAX对象
var xhr = new XMLHttpRequest();
xhr.onload = function() {
alert("上传成功！");
}
xhr.open("POST", "upload.php", true);
// 发送表单数据
xhr.send(formData);
|
上传到服务器之后，获取到文件列表为：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
| Array
(
[jpg_jpg] => Array
(
[name] => jpg.jpg
[type] => image/jpeg
[tmp_name] => D:\xampp\tmp\phpA595.tmp
[error] => 0
[size] => 133363
)
[png_png] => Array
(
[name] => png.png
[type] => image/png
[tmp_name] => D:\xampp\tmp\phpA5A6.tmp
[error] => 0
[size] => 1214628
)
)
|
在服务端循环遍历这个数组就可以上传文件了。