Using Checkboxes to Make Forms More Friendly
Checkboxes default to being checked when they are active. Many web documents have these types of controls. You can change their appearance to make them more rounded and make the labels clear for your users. Checkboxes differ from radio buttons because you can select multiple checkboxes simultaneously.
Additional attributes
In addition to the common attributes shared by all <input> elements, "checkbox" inputs support the following attributes.
checked-
A boolean attribute indicating whether this checkbox is checked by default (when the page loads). It does not indicate whether this checkbox is currently checked: if the checkbox's state is changed, this content attribute does not reflect the change. (Only the
HTMLInputElement'scheckedIDL attribute is updated).Note: Unlike other input controls, a checkbox's value is only included in the submitted data if the checkbox is currently
checked. If it is, then the value of the checkbox'svalueattribute is reported as the input's value, oronif novalueis set. Unlike other browsers, Firefox by default persists the dynamic checked state of an<input>across page loads. Use theautocompleteattribute to control this feature. value-
The
valueattribute is one which all<input>s share; however, it serves a special purpose for inputs of typecheckbox: when a form is submitted, only checkboxes which are currently checked are submitted to the server, and the reported value is the value of thevalueattribute. If thevalueis not otherwise specified, it is the stringonby default. This is demonstrated in the section Value above.