When learning or speaking English, most people do not realise the vast differences between American and British versions of the language. Though the original 'correct' grammar originally comes from old British English, grammar is constantly changing and many new ways of using grammar are coming from across the pond from American influence through the media and internet.
Both types of language structure can be considered right, though in British and American education systems there are different rules depending on which English is being taught. There are various differences in spelling and punctuation, but this does not affect the spoken language as the grammar, vocabulary and pronunciation differences do.