In a regular HTTP response, the Content-Disposition
response header is a header indicating if the content is expected to be displayed inline in the browser, that is, as a Web page or as part of a Web page, or as an attachment, that is downloaded and saved locally.
In a multipart/form-data
body, the HTTP Content-Disposition
general header is a header that can be used on the subpart of a multipart body to give information about the field it applies to. The subpart is delimited by the boundary defined in the Content-Type
header. Used on the body itself, Content-Disposition
has no effect.
The Content-Disposition
header is defined in the larger context of MIME messages for e-mail, but only a subset of the possible parameters apply to HTTP forms and POST
requests. Only the value form-data
, as well as the optional directive name
and filename
, can be used in the HTTP context.
Header type | Response header (for the main body) General header (for a subpart of a multipart body) |
---|---|
Forbidden header name | no |
Syntax
As a response header for the main body
The first parameter in the HTTP context is either inline
(default value, indicating it can be displayed inside the Web page, or as the Web page) or attachment
(indicating it should be downloaded; most browsers presenting a 'Save as' dialog, prefilled with the value of the filename
parameters if present).
Content-Disposition: inline Content-Disposition: attachment Content-Disposition: attachment; filename="filename.jpg"
As a header for a multipart body
The first parameter in the HTTP context is always form-data
. Additional parameters are case-insensitive and have arguments that use quoted-string syntax after the '='
sign. Multiple parameters are separated by a semi-colon (';'
).
Content-Disposition: form-data Content-Disposition: form-data; name="fieldName" Content-Disposition: form-data; name="fieldName"; filename="filename.jpg"
Directives
name
- Is followed by a string containing the name of the HTML field in the form that the content of this subpart refers to. When dealing with multiple files in the same field (for example, the
multiple
attribute of an<input type="file">
element), there can be several subparts with the same name. - A
name
with a value of'_charset_'
indicates that the part is not an HTML field, but the default charset to use for parts without explicit charset information. filename
- Is followed by a string containing the original name of the file transmitted. The filename is always optional and must not be used blindly by the application: path information should be stripped, and conversion to the server file system rules should be done. This parameter provides mostly indicative information. When used in combination with
Content-Disposition: attachment
, it is used as the default filename for an eventual "Save As" dialog presented to the user. filename*
-
The parameters
filename
andfilename*
differ only in thatfilename*
uses the encoding defined in RFC 5987. When bothfilename
andfilename*
are present in a single header field value,filename*
is preferred overfilename
when both are understood.
Examples
A response triggering the "Save As" dialog:
200 OK Content-Type: text/html; charset=utf-8 Content-Disposition: attachment; filename="cool.html" Content-Length: 21 <HTML>Save me!</HTML>
This simple HTML file will be saved as a regular download rather than displayed in the browser. Most browsers will propose to save it under the cool.html
filename (by default).
An example of an HTML form posted using the multipart/form-data
format that makes use of the Content-Disposition
header:
POST /test.html HTTP/1.1 Host: example.org Content-Type: multipart/form-data;boundary="boundary" --boundary Content-Disposition: form-data; name="field1" value1 --boundary Content-Disposition: form-data; name="field2"; filename="example.txt" value2 --boundary--
Specifications
Specification | Title |
---|---|
RFC 7578 | Returning Values from Forms: multipart/form-data |
RFC 6266 | Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP) |
RFC 2183 | Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Content-Disposition | Chrome Full support Yes | Edge Full support 12 | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
Compatibility notes
- Firefox 5 handles the
Content-Disposition
HTTP response header more effectively if both thefilename
andfilename*
parameters are provided; it looks through all provided names, using thefilename*
parameter if one is available, even if afilename
parameter is included first. Previously, the first matching parameter would be used, thereby preventing a more appropriate name from being used. See bug 588781.
See also
- HTML Forms
- The
Content-Type
defining the boundary of the multipart body. - The
FormData
interface used to manipulate form data for use in theXMLHttpRequest
API.