From W3C Wiki
The form element represents a user-submittable form.
- Some of which can represent editable values that can be submitted to a server for processing.
accept-charset= list of character-encoding names
gives the character encodings that are to be used for the submission.
action= valid URL potentially surrounded by spaces
Specify the form-submission action for the element.
autocomplete= on/ off
Specifies whether the element represents a form for which by default a UA is meant to store the values entered into its input elements by the user (so that the UA can pre-fill the form later).
The on state indicates that the value is not particularly sensitive and the user can expect to be able to rely on his user agent to remember values he has entered for that control.
The off state indicates either that the control's input data is particularly sensitive (for example the activation code for a nuclear weapon); or that it is a value that will never be reused (for example a one-time-key for a bank login) and the user will therefore have to explicitly enter the data each time, instead of being able to rely on the UA to prefill the value for him; or that the document provides its own autocomplete mechanism and does not want the user agent to provide autocompletion values.
enctype= application/x-www-form-urlencoded / multipart/form-data / text/plain
Specfy a MIME type with which a UA is meant to associate this element for form submission.
The missing value default for these attributes is the application/x-www-form-urlencoded state.
method= get/ post
Specify the HTTP method with which a UA is meant to associate this element for form submission.
The missing value default for this attributes is the GET state.
Indicating the HTTP GET method.
Indicating the HTTP POST method.
Gives the name of the input element.
If present, they indicate that the form is not to be validated during submission.
target= valid browsing context names or keywords
Specfy a browsing context name or keyword that represents the target of the control.
<form action="http://www.google.com/search" method="get"> <label>Google: <input type="search" name="q"></label> <input type="submit" value="Search..."> </form>
The HTML5 specification defines the <form> element in 4.10.3 The form element.