jQuery判断至少有一个checkbox被选中的方法

<form>
  <!-- bunch of checkboxes like: -->
  <input type="checkbox" ... >
  <input type="checkbox" ... >
  <!-- submit button, defaults to disabled -->
  <input type="submit" value="submit">
</form>

var checkboxes = $("input[type='checkbox']"),
  submitButt = $("input[type='submit']");
checkboxes.click(function() {
  submitButt.attr("disabled", !checkboxes.is(":checked"));
});