Section for Week 6, Tuesday, 2/16/99

Form related tags and their attribute modifiers:

Top level elements: FORM, INPUT, SELECT, and TEXTAREA.  Their modifiers are:

FORM
<FORM ACTION="script.cgi" METHOD="GET">

INPUT
Text Field: INPUT TYPE=TEXT
Required attributes are: 
NAME 
     name for the form field corresponding to this element. 
The optional attributes are: 
MAXLENGTH constrains the number of characters that can be entered into a
     text input field. If the value of MAXLENGTH is greater the the value of
     the SIZE attribute, the field should scroll appropriately. The default
     number of characters is unlimited.  
SIZE specifies the amount of display space allocated to this input field
     according to its type. The default depends on the user agent.  VALUE
     The initial value of the field.

<p>Street Address: <input name=street><br>
Postal City code: <input name=city size=16 maxlength=16><br>
Zip Code: <input name=zip size=10 maxlength=10 value="99999-9999"><br>

Password Field: INPUT TYPE=PASSWORD
An INPUT element with `TYPE=PASSWORD' is a text field as above, except that
the value is obscured as it is entered.

Check Box: INPUT TYPE=CHECKBOX

An INPUT element with `TYPE=CHECKBOX' represents a boolean choice. A set of
such elements with the same name represents an n-of-many choice
field. Required attributes are:
NAME 
     symbolic name for the form field corresponding to this element or group
     of elements. 
VALUE 
     The portion of the value of the field contributed by this element. 

Optional attributes are: 

CHECKED 
     indicates that the initial state is on. 

For example: 

<p>What flavors do you like?
<input type=checkbox name=flavor value=vanilla>Vanilla<br>
<input type=checkbox name=flavor value=strawberry>Strawberry<br>
<input type=checkbox name=flavor value=chocolate checked>Chocolate<br>

As many checked name/value pairs will be returned as are checked.

Radio Button: INPUT TYPE=RADIO

An INPUT element with `TYPE=RADIO' represents a boolean choice. 
Optional: CHECKED 
     indicates that the initial state is on. 

Image Pixel: INPUT TYPE=IMAGE

An INPUT element with `TYPE=IMAGE' specifies an image resource to display,
and allows input of two form fields: the x and y coordinate of a pixel
chosen from the image. The names of the fields are the name of the field
with `.x' and `.y' appended. `TYPE=IMAGE' implies `TYPE=SUBMIT' processing;
that is, when a pixel is chosen, the form as a whole is submitted.

The NAME attribute is required as for other input fields. The SRC attribute
is required and the ALIGN is optional as for the IMG element (see section
Image: IMG).

For example: 

<p>Choose a point on the map:
<input type=image name=point src="map.gif">

Hidden Field: INPUT TYPE=HIDDEN

An INPUT element with `TYPE=HIDDEN' represents a hidden field.

Submit Button: INPUT TYPE=SUBMIT

An INPUT element with `TYPE=SUBMIT' represents an input option, typically a
button, that
instructs the user agent to submit the form. Optional attributes are: 

NAME 
     indicates that this element contributes a form field whose value is
     given by the VALUE
     attribute. If the NAME attribute is not present, this element does not
     contribute a form field. 
VALUE 
     indicates a label for the input (button). 

You may submit this request internally:
<input type=submit name=recipient value=internal><br>
or to the external world:
<input type=submit name=recipient value=world>

Reset Button: INPUT TYPE=RESET

An INPUT element with `TYPE=RESET' represents an input option, typically a
button, that instructs the user agent to reset the form's fields to their
initial states. The VALUE attribute, if present, indicates a label for the
input (button).

Selection: SELECT

The SELECT element constrains the form field to an enumerated list of
values. The values are given in OPTION elements. Attributes are:

MULTIPLE 
     indicates that more than one option may be included in the value. 
NAME 
     specifies the name of the form field. 
SIZE specifies the number of visible items. Select fields of size one are
     typically pop-down
     menus, whereas select fields with size greater than one are typically
     lists. 

Option: OPTION

The Option element can only occur within a Select element. It represents one
choice, and has the following attributes:

SELECTED 
     Indicates that this option is initially selected. 
VALUE 
     indicates the value to be returned if this option is chosen. The field
     value defaults to the content of the OPTION element. 

The content of the OPTION element is presented to the user to represent the
option. It is used as a returned value if the VALUE attribute is not
present.

Text Area: TEXTAREA

The TEXTAREA element represents a multi-line text field. Attributes are: 

COLS 
     the number of visible columns to display for the text area, in
     characters. 
NAME 
     Specifies the name of the form field. 
ROWS 
     The number of visible rows to display for the text area, in
     characters.