getting radio , check box in prototype?

how can i get the checkbox, radio button, pu开发者_StackOverflow社区lldown menu values using id with using form in prototype js?

See $F

Edit
$F get's the text value of an element by it's ID. For example if you had a drop down select box called "month" you could use $F('month') to get it's value "February".

In response to your follow up question, "how can i get the count of number of check box is selected" use this:

$$('input:checked').length

$F returns the value of a form field.

Given

<input id="field1" name="field1" value="foo">

This is true:

$F('field1') == 'foo'

Given

<input type="checkbox" name="mycheckbox1" id="mycheckbox1" value="ABC" checked/>
<input type="checkbox" name="mycheckbox2" id="mycheckbox2" value="DEF"/>

This is true:

$F('mycheckbox1') == "ABC"
$F('mycheckbox2') == null