oc 无中生有添加协议

    @protocol MyClassJavaScriptMethods <JSExport>

    - (void)foo;

    @end

    @interface MyClass : NSObject <MyClassJavaScriptMethods>

    - (void)foo;

    - (void)bar;

    @end

class_addProtocol([UIButton class],@protocol(UIButtonExport));

@protocol UIButtonExport <JSExport>

- (void)setTitle:(NSString *)title forState:(UIControlState)state;

- (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state;

@end