Slashes are a common calendar date separator used across many countries and by some standards such as the Common Log Format used by web servers. Depending on context, it may be in the form Day/Month/Year, Month/Day/Year, or Year/Month/Day. If only two elements are present, they typically denote a day and month in some order. For example, 9/11 is a common American way of writing the date 11 September and has become shorthand for the attacks on New York and Washington, DC, which occurred on a day Britons write as 11/9/2001. Owing to the ambiguity across cultures, the practice of using only two elements to denote a date is sometimes proscribed.