Search element <select> only

[chung1905]

Hello,

First thing I want to say is this repository is very helpful, an open source country/region data. Thank you so much.
Then, here's my small pull request:

• Because in the code, we write somethings like: countryElement.options[countryElement.length] = new Option(countries[i][0], val); without checking if options has been defined or not.
• I know countryElement always has options attribute if it's element. But if it is not, some unfriendly logs will be shown in console. => I have made a small commit to query .crs-country on elements only.

  Thank you again for the repository.

  Edit: typos