标准
HTML 5 form label wants an ID to link the label to the input.
<form> <label for="male">Male</label> <input type="radio" id="male"/> <label for="female">Female</label> <input type="radio" id="female"/> </form>
正如大多数JS开发人员所知,using IDs leaks globals – 在这种情况下,创建了window.male和window.female.
