INPUT
The INPUT element represents a field
whose contents may be edited by the
user. It has the following attributes.
- NAME
- Symbolic name used when transferring
the form's contents. This attribute
is always needed and should uniquely
identify this field.
- TYPE
- Defines the type of data the
field accepts. Defaults to free text.
- SIZE
- Specifies the size or precision
of the field according to its type.
- MAXLENGTH
- The maximum number of characters
that will be accepted as input. This
can be greater that specified by
SIZE , in which case the field will
scroll appropriately. The default
is unlimited.
- VALUE
- The initial value for the field,
or the value when checked for checkboxes
and radio buttons. This attribute
is required for radio buttons.
- SRC
- A URL or URN specifying an image
- for use only with TYPE=IMAGEMAP.
- ALIGN
- Vertical alignment of the image
- for use only with TYPE=IMAGEMAP.
Propsed
- CHECKED
- When present indicates that
a checkbox or radio button is selected.
- DISABLED
- When present indicates that
this field is temporarily disabled.
Browsers should show this by "greying
it" out in some manner.
- ERROR
- When present indicates that
the field's initial value is in error
in some way, e.g. because it is inconsistent
with the values of other fields.
Servers should include an explanatory
error message with the form's text.
Types
The following types of fields can
be defined with the TYPE attribute
:
- TEXT
- Single line text entry fields.
Use the SIZE attribute to specify
the visible width in characters,
e.g. SIZE="24" for a 24 character
field. The MAX attribute can be used
to specify an upper limit to the
number of characters that can be
entered into a text field, e.g. MAX=72
. Use the TEXTAREA element for text
fields which can accept multiple
lines (see below).
- HIDDEN
- No field is presented to the
user, but the content of the field
is sent with the submitted form.
This value may be used to transmit
state information about client/server
interaction.
- CHECKBOX
- Used for simple Boolean
attributes, or for attributes which
can take multiple values at the same
time. The latter is represented by
a number of checkbox fields each
of which has the same NAME .
- RADIO
- For attributes which can take
a single value from a set of alternatives.
Each radio button field in the group
should be given the same NAME .
- SUBMIT
- This is a button that when
pressed submits the form. It offers
authors control over the location
of this button. You can use an image
as a submit button by specifying
a URL with the SRC attribute.
- RESET
- This is a button that when
pressed resets the form's fields
to their initial values as specified
by the VALUE attribute. You can use
an image as a reeset button by specifying
a URL with the SRC attribute.
Proposed types
- RANGE
- This allows you to specify
an integer range with the MIN and
MAX attributes, e.g. MIN=1 MAX=100
. Users can select any value in this
range.
- INT
- For entering integer numbers,
the maximum number of digits can
be specified with the SIZE attribute
(excluding the sign character), e.g.
size=3 for a three digit number.
- FLOAT
- For fields which can accept
floating point numbers.
- SCRIBBLE
- A field upon which you can
write with a pen or mouse. The size
of the field in millimeters is given
as SIZE= width , height. The units
are absolute as they relate to the
dimensions of the human hand, rather
than pixels of varying resolution.
The scribble may involve time and
pressure data in addition to the
basic ink data. You can use scribble
for signatures or sketches. The field
can be initialised by setting the
SRC attribute to a URL which contains
the ink *2 . The VALUE attribute
is ignored.
- AUDIO
- This provides a way of entering
spoken messages into a form. Browsers
might show an icon which when clicked
pops-up a set of tape controls that
you can use to record and replay
messages. The initial message can
be set by specifying a URL with the
SRC attribute. The VALUE attribute
is ignored.
Obsolete types
- DATE
- Fields which can accept a recognized
date format.
- URL
- For fields which expect document
references as URLs or URNs.
- IMAGE
- This allows you to specify
an image field upon which you can
click with a pointing device. The
SRC and ALIGN attributes are exactly
the same as for the IMG and IMAGE
elements. The symbolic names for
the x and y coordinates of the click
event are specified with .x and .y
for the given with the NAME attribute.
The VALUE attribute is ignored.
When you need to let users enter
more than one line of text, you should
use the TEXTAREA element.