[jQuery] Change mask onclick, how do ?

[jQuery] Change mask onclick, how do ?

<div dir="ltr">Hi guys
I have the problem when go change de mask, i`m using maskedinput
<a href="http://digitalbush.com/projects/masked-input-plugin/">http://digitalbush.com/projects/masked-input-plugin/</a>
my code:
<input name="tip" type="radio"  id="tip_j" title="Jurídica" value="J"/>Jurídica

<input name="tip" type="radio"  id="tip_f" title="Física"   value="F"/>Física
$("#tip_j").click(function(){
    $("#masked").val("");                               
    $("#masked").mask("999.999.999/9999-99");
});
$("#tip_f").click(function(){
    $("#masked").val("");                               
    $("#masked").mask("999.999.999-99");
});
the mask change, but not function and is a problem..
</div>