a. Basic consideration
         Nowadays people have two or more languages or called bilingual. Many people usually mix their language to other language. Used code mixing usually to make they look educated or even prestige. People who know one or two languages are bilingual and multilingual is people who know two or more languages. According to Weinrich (Aslinda, dkk., 2007:23) said that bilingual is The practice of alternately using two language, it means a habit uses two language alternating way. While multilingual is refers to people who known more than two languages, even the language could be three, or four, even five languages at once.
       According to Kridalaksana (1984: 32) code mixing is using of language unit from one language to other language to expand the style of language or language variety; including the use of words, phrases, idioms. The speaker used code mixing to expand the style of language such as Indonesian mixing with English or Japan. This research uses sociolinguistic approach and to make this research more relevant. According Suwito (in Rohmadi. 2004: 60 ) “Code mixing is the use of two or more languages by entering the pieces of language to another while the pieces which inserts do not have function”.
     Code mixing can be finding in social network as written language, it also will found in newspaper, magazine, novel, internet media and etc. code mixing also has spoken language such as in radio program, Television program, teaching-learning process, cinema etc. This study is about code mixing that happened in social network, but the researcher focuses on the code mixing between Indonesia and Japan by anime lovers. In Facebook we will found much code mixing, when other people do chatting. Facebook deploy increasing code mixing custom in Indonesia. From those reasons above, the researcher is interested to finding out code mixing that occurred in Facebook. Especially code mixing between indonesia – japan by anime lovers in social network (facebook).
      The writer would like to study code mixing in Facebook deeply. Therefore, the writer wanted to answer the following question: What are the forms of code mixing in Facebook by anime lovers? Through this study, the writer expects that the findings may be useful to enrich our knowledge about code mixing in Facebook.

b. Research Question
      Based on the background above, the researcher will discuss and observe some problem, there are the Problems:

• What Is Code mixing?
• What are types of code mixing between Indonesian and Japan used by anime lovers?
• Why does code mixing between Indonesian and Japan happened?

c. Objective of research
       This research aims to know what code is mixing by anime lovers, why does code mixing happened. Code mixing is not only English, but also in other language. For example code mixing between Indonesia - Korea, Indonesia - Japan, etc. Code mixing Indonesia - English will find in a circle of artist, teacher, students even everybody who has bilingual or multilingual. In this research we will discuss about code mixing between Indonesian - Japan. Especially circle of anime lovers in social network. Anime lovers are people who loves cartoon from Japan, the researcher will provide the causing factor of code mixing in social network by anime lovers. By this research, the reader could obtain the information about types of code mixing between Indonesian and Japan used by anime lovers. And also give the information about factors that engendered the anime lovers used code mixing.

d. Literary review
       Devel P. Trudgill (1974: 32) "Sociolinguistics is that part of linguistics which is concerned with language as a social and cultural phenomenon. It investigates the field of language and society & has close connections with the social sciences, especially social psychology, anthropology, human geography and sociology."
       Wm. Downes (1984: 15), Language and Society said that “Sociolinguistics is that branch of linguistics which studies just those properties of language and languages which REQUIRE reference to social, including contextual, factors in their explanation."

• Multilingualism

            A person who has ability to speak three or more languages is called multilingual (Pateda, 1990:57). Code mixing usually occurs in bilingual or multilingual community or society and the function (meaning) of the languages cannot be clearly separated. This code mixing is used when the conversant use both languages together to the extent that they change from one language to the other in the course of a single utterance (Wardhaugh, 1986: 103)

• Code mixing

          Kridalaksana (1984: 32) code mixing is using of language unit from one language to other language to expand the style of language or language variety; including the use of words, phrases, idioms. In code mixing the main code or basic code has its own function and meaning, other codes, however, are only the pieces, without function and meaning as a code (Chaer, 1995: 151).
          In code mixing the main code or basic code has its own function and meaning, other codes, however, are only the pieces, without function and meaning as a code (Chaer, 1995: 151).
Code switching and code mixing can also be used to express group identity. As it has been mentioned previously, the way of communication of academic people in their disciplinary groupings, are obviously different from other groups. In other words, the way of communication of one community is different from the people who are out of the community (Barnett, 1994: 7).

• Types of code mixing

      Code mixing is converging elements of the language that is derived from several languages which has stripped language functions and has a function to support the language that be mixing. This element can be divided into two:
1. the elements that come from the original language with all its variations (inner code mixing)
2. Ingredient that comes from a foreign language (outer code mixing)

• Causing factors using code mixing

      According to Suwito(1985:77) the background of code mixing happened divided into two types.
1. (Attitudinal type) is a background type on the speaker’s attitude. This Type includes (1) refining the expression; (2) to demonstrate the ability, (3) the introduction and development of a new culture.
2. (Linguistic type) is a background of language. This Type include (1) more easy to remember; (2) has not result of homonymy; (3) the limitations of the word; (4) the consequent or desire the result.
     Meanwhile, according to Nababan (1984:32) code mixing occurs because (1) the speaker want to show off, (2) relaxation, (3) there is no proper expression in the language that is being used, so the need to use words or phrases from a foreign language.

e. Methodology of Research
       The researcher observes code mixing in social network. This research uses qualitative method because this research aims to know the types of code mixing between Indonesian and Japan used by anime lovers.
       The population of the study is male and female facebooker in Facebook And the sample of the study consist the chatter in Facebook. The writer chooses this data because they use two languages (Indonesian and japan) to communicate with each other.
1. The source of the data
The data in this research were obtained from facebook, twitter, e-books, interview, and internet.
2. Technique of collecting data
 Interviewing the facebooker by chatting.
 Recording the chat and the wall.
 Transcribing the recorded data
 Analyzing code-mixing that occur in the data based on the theory.
f. Data and Data Analysis
1. Data
    The data of this research uses observation. The researcher will do the observation of the use of code mixing between Japan and Indonesia language by anime lovers and the researcher will do the interview for some of them especially in a circle of anime lovers.
Here some data
Some words of japan that usually using by anime lovers in social network.
Words Meaning

• Ohayou Good morning
• Konnichiwa Good afternoon
• Konbanwa Good night
• Gomennasai / Gomen Sorry
• Ganbatte ne! Fighting
• hontou? Really?
• sugoii Cool
• Arigatou gozaimasu Thank you
• onee-san Old sister
• onii-san Old brother
• O yasumi nasai. Good night
• Ja ne ! / Mata ne! See you!
• Dou itashimashite! You are welcome
• Onegai shimasu Please help me
• sumimasen Sorry
• demo but
• Wakatta Understand
• kawaii Beautiful
• Watashi Me
• Yatta Passionate

2. Data analysis
Transcription of the data facebook wall and chat
1. Correspondent: female, Gorontalist , student
Dominant language: Indonesian
Facebook chat
“Sumimasen, belum bisa ikut sebentar demo minggu depan pasti datang. Ok”.
Analysis: in this sentence researcher found code mixing between japan and indonesia. Those words are “sumimasen” and “demo”. It means she said sorry cannot came to Gath, word demo means but, so she promise next week she will came. She using code mixing between indonesia and japan in a circle of anime lovers. I found this chat when she chats with her friends who also love anime or japan.
2. Correspondent: female, Gorontalist , student university
Dominant language: Indonesian
Facebook wall
“Ohh...oniichan status yang ini toh?? ooww~wakattaaa”
Analysis: in this correspondent two, she is a multilingual and knows japan language. Oniichan means old brother, she using code mixing because her interlocutors also know japan language. The word “wakatta” expressing that she understand.
3. Correspondent: female, Bandung, student
Dominant language: Indonesian
Facebook Wall
wah yang ini kawaii neechan. . .aku tag ya. .
Analysis: in this sentence researcher found two japan words. Those words are ”kawaii” and “neechan”. In correspondent three she admires a photo in a facebook and she said kawaii (beauty). In this sentence she uses code mix between three languages; there are Indonesia, japan and English. The word” tag” expressing to get the picture or photo from facebook.
4. Correspondent: male, Javanese , student
Dominant language: Indonesian
Facebook Wall
Hadir mamen watashi wa kaza desu
Analysis: this sentence was found on the group of anime lovers, he account facebook name is kaza so when he join in that group he was introducing his name using code mixing between indonesia and japan. The word watashi means me. The speaker uses grammatical japan language. The words “wa” and “desu” are an auxiliary word.
5. Correspondent: female, Javanese, student
Dominant language: Indonesian
Facebook Wall
horee yattaa… kyo, jalan-jalan, arigatou gozaimasu nechaan..
Analysis: there are some of japan words that mixing in Indonesia language. In correspondent five, she mixing japan but the forming of that sentences used indonesia language. The word “yatta” expressing happiness and word “kyo” means this day, and then she said arigatou gozaimasu for her old sister (neechan).

g. Finding and discussion

• What is code mixing

Code mixing is mix one language to other language, according to Kridalaksana (1984: 32) code mixing is using of language unit from one language to other language to expand the style of language or language variety; including the use of words, phrases, idioms. In code mixing the main code or basic code has its own function and meaning, other codes, however, are only the pieces, without function and meaning as a code (Chaer, 1995: 151). The code mixing that researcher found only happened in a circle of anime lovers. Some of them as a sample is really love anime from she was children. Because of watch anime she obtain some of words of Japan.
Anime lovers in social network, especially on facebook, they usually join with some of group of anime lovers. In that group their shared about anime, culture, picture even study Japan language together. The researcher found code mixing between japan and indonesia on facebook wall or comment of some group anime lovers, sometimes they using all the language of japan. The data in this study is collecting from some group of anime lovers on facebook, and the researcher clarification the words that always they used to mixing to Indonesia.

• What are types of code mixing between Indonesian and Japan used by anime lovers

The types of code mixing divided into inner code mixing and outer code mixing. Inner code mixing are the elements that come from the original language with all its variations, while outer code mixing is Ingredient that comes from a foreign language. This study focuses of outer code mixing; japan language is from foreign language, so the researcher found the outer code mixing in some group of anime lovers languages.
According to (Suwito: 1983) the form of code mixing include; (1) the insertion of the word, (2) insertion phrases, (3) insertion of clause, (4) The insertion of the phrase or idiom, (5) Insertion baster form (native and foreign joint formation).
In this study the researcher found some types of code mixing. There are insertion word, phrases, and clauses. The insertion of word “aku belum bisa demo besok mungkin bisa” the speakers put a word “demo” in the center of sentence. The example of insertion of phrase “huh,,, chotto matte, coba di cek lagi” chotto matte means wait a second. It’s a phrase that put in the sentence. And the last type’s code mixing between japan and indonesia is the insertion of clauses. The insertion of clause is “Hadir mamen watashi wa kaza desu”. In this sentences the speaker insertion clause. A clause is a grammatical unit consisting of a subject (S) and a predicate (P) either with the object (O). The word watashi means me. The speaker uses grammatical japan language, and the words “wa” and “desu” are an auxiliary word.

• Why does code mixing between Indonesia and Japan happened

Many anime lovers usually mix their language between Indonesia and Japan when they chat with a friend who also loves anime, according to Nababan (1984:32) code mixing occurs because (1) the speaker want to show off, (2) relaxation, (3) there is no proper expression in the language that is being used, so the need to use words or phrases from a foreign language.
Anime lovers uses code mixing in the language is to make the other facebokers will see if she has been watching many anime or to show off that they are anime lovers, through watching anime they will get some vocabularies which always used, for example kawaii (beauty), sugoii. (Cool), etc. Anime lovers fellow, they also exchange information about vocabulary of japan. Even study together about japan language.

h. Conclusion
       From the analysis above the researcher found that the dominant type of code-mixing used by anime lovers are mix language between Japan and Indonesian in a sentence. I think why they mix Japan language to indonesia sentences just for to show up. They want to show up to anime fellow lovers and other facebookers if they have been watching many anime and know japan langauge. Facebook have an important role for develop code mixing custom. Why? It’s because the researcher found much code mixing process in Facebook. Such as code mixing japan and indonesia or English and japan etc.
       Some of anime lovers have knowledge of japan language, but some of them just study from watching anime, an anime lover will proud if he/she has been watching many anime from japan, they will know the culture of foreign countries, especially the country that have given anime & manga. Anime lovers also want to Applying culture / customs of the country considered positive discipline and hard work it in everyday life as cultural say sorry and thank you, friendly etc.
Code mixing that the researcher found has the quality like Japan, in japan they will say sorry if they make a fault, “gomennasai saya tidak bermaksud seperti itu” and always say thank you if somebody helped. If two anime lovers meet, they will easy to making friend.

i. References
Whardhaugh, Ronald. (2002). ed. 4th. An Introduction to Sociolinguistics. UK: Blackwell Publishers.
Research of Jatut Prameswari types of code mixing (suwito: 1983) http://www.academia.edu Access 01th of May 2014
Suwito: 1983 http://hensursuryani.blogspot.com/2013/01/code-mixing.html access 21th of may 2014
MUMTAHANAH EVA (2011) “Code Mixing and Code Switching In Bam’s Logging House” Access 15th of May 2014