[jQuery] Best way to Toggle

[daweb]

Hi everybody and sorry about my English!

This is my markup:

<fieldset id="id_1">
<dl class="campo-esteso">
<dt>&nbsp;</dt>
<dd>
<input name="flag" type="checkbox" class="flag" id="flag" value="on"
tabindex="1"  />
<span class="opzionale">Toggle?!?!</span>
</dd>
</dl>
</fieldset>

<fieldset id="id_2"> // this fieldset is hidden
Some input text type
</fieldset>

I have 3 similar checkbox field next. What about the best way to
toggle the next fieldset element.

I'd try this, but it doesn't works:

$(':checkbox').click(function(){
$(this).parent('fieldset').slideToggle();
});

Thank you all.