How to use hook_init in a custom module?
Some suggestions:


Is the module enabled? Silly question, but I've forgotten to do that before.
hook_init implementations won't get called until you clear the cache. Did you clear the cache?
I will sometimes put a drupal_set_message('this line'); in various parts of the code to see if that's getting called. In situations where a drupal_set_message isn't helping, I sometimes will put a asdf() so I can get a "fatal error, call to undefined function" message. Then it's really clear whether or not the code is getting called.
If the hook_init is not being called and the module is enabled and cache was cleared, then it's probably mis-spelled. The function should be named based on the name of your module: If your module is mymodule.module then the function name is mymodule_init().
It's possible that the path you are using isn't quite right. Does the file really exist there? I would try: drupal_set_message(drupal_get_path('modules', 'myInfo') . '/myScript.js'); so you can see the path and confirm that it's right.
There's some good documentation on Managing JavaScript in Drupal 7 though perhaps you've already read that page.


Good luck!