jQuery zip masking for multiple formats

This zip code is actually simple, but when you have a more complex format to handle, here is how it's solved with the plugin (from the demo page):

var options =  {onKeyPress: function(cep, e, field, options){
  var masks = ['00000-000', '0-00-00-00'];
    mask = (cep.length>7) ? masks[1] : masks[0];
  $('.crazy_cep').mask(mask, options);
}};

$('.crazy_cep').mask('00000-000', options);

You don't have to use a different plug-in. Just move the question mark, so that instead of:

$('#myZipField').mask("?99999-9999");

you should use:

$('#myZipField').mask("99999?-9999");

After all, it isn't the entire string which is optional, just the - and onward.