how to make vim ctags works for modern javascript
Like the others had said: DoctorJS (formerly jsctags) is the best option.
However, integrating it with Vim by writing custom wrappers or using Vim-taglist-plus plugin, which isn't currently working, aren't good solutions.
The easiest way I've found is to install the TagBar Vim plugin (NOTE: It's TagBar, not the old infamous TagList!).
See my other answer for more info.
Edit:
There's a new project called tern.js which should replace the dead doctor.js. See the link above for more info.
As @Benoit answered, you can always setup a new languages for ctags; however in the case of JavaScript, you may want to try DoctorJS (formerly jsctags). From the author it is a limited JS environment that records all the functions and objects your script made and turns them into vim-compatible tags file. Here is the original post http://pcwalton.blogspot.com/2010/05/introducing-jsctags.html and its website: http://doctorjs.org/.
To use it with ctags I have to rename the ctags file to smt like ex-ctags and write a wrapper script named ctags which will switch the tool depending on --language.