Friends who do web pages will encounter this situation: Sometimes they have worked hard for a long time, especially some JavaScript special effects, which is easy to use to view source files. So how can you prevent the source code from being viewed? We can use the Event.Button feature. The following table is the possible value and meaning of the event.button attribute: Possible value meaning possible value value 0 No button 1 Press the left button 2 Press the right button 3 Press the left and right-click 4 Press the middle key 5 Press the left and intermediate keys 6 Press the right and middle Key 7 Press all the keys to refer to the top table, we can add the following statement between
and :