jQuery see if any or no checkboxes are selected

JQuery .is will test all specified elements and return true if at least one of them matches selector:

if ($(":checkbox[name='choices']", form).is(":checked"))
{
    // one or more checked
}
else
{
    // nothing checked
}

You can use something like this

if ($("#formID input:checkbox:checked").length > 0)
{
    // any one is checked
}
else
{
   // none is checked
}