Welcome to the forum, Albert Song
We do not know that system as the DJ System. It is the International Phonetic Alphabet. (IPA) Daniel Jones was one of the pople who worked on the development of the IPA.I know in UK you h​ave a system called DJ(Daniel Jones) phonetic alphabet, which is now included in the <Cambridge pronuncing dictionary>.
There were attempts once to teach reading with the help of a simplified, near-phonetic alphabet, The Initial Teaching Alphabet, but that did not achieve widespread acceptance. Various systems of teaching children to read over the years, including teachers modelling whole-word pronunciation, have been tried, but generally most children have learnt to read by learning the sounds generally denoted by individual letters. Written English is nowhere near as phonetic as, for example, Czech or Italian, but many of the consonants are mainly used for only one sound. B/b, for example is usually pronounced /b/. Even the individual vowels have only about three common sounds associated with them. The system therefore is nothing like as difficult to learn as, for example Chinese, where learners have to learn the individual pronunciation of every single ideogram. Thus, although some native speakers never learn how to write with 100% accurate spelling, most have reasonable reading proficiency by the age of about eight. Chinese speakers coming across a word they have never seen before have no idea how it is pronounced until they have been told. English speakers, however, encountering drock for the first time will have no problem at all in pronouncing it correctly.But according to many here in China who are now living in UK/US or once did, school kids in US/UK don't learn any phonetic alphabet at all, they just copy a teacher's pronunciation of each word. is that true?

Student or Learner