TYPE = RADIO
RADIO is used to create a series of choices of which only one can be selected.
The term "radio button" comes from the buttons for the radio in an automobile, where selecting one radio station automatically de-selects all the others.
HTML radio buttons are created by using several
<INPUT TYPE=RADIO>
buttons, all with the same
name, but with different values. For example, this series of buttons allows you to choose one size for a pizza:
| this code |
produces this |
<FORM ACTION="../cgi-bin/mycgi.pl">
What size pizza?<P>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="S">small<BR>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="M">medium<BR>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="L">large<P>
<INPUT TYPE=SUBMIT VALUE="submit">
</FORM>
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Note that it is the content of the VALUE attribute that is sent to the CGI,
not whatever text happens to appear next to the radio button.
If one of the items should be the default selection, use the
CHECKED attribute:
| this code |
produces this |
<FORM ACTION="../cgi-bin/mycgi.pl">
What size pizza?<P>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="S" >small<BR>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="M" CHECKED >medium<BR>
<INPUT TYPE=RADIO NAME="pizzasize" VALUE="L" >large<P>
<INPUT TYPE=SUBMIT VALUE="submit">
</FORM>
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If no CHECKED attribute is used, different browsers have different ways of displaying the initial state of a series of
radio buttons. Netscape and MSIE have none of the buttons selected. Mosaic
selects the first button.
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