javascript - Variable outside function scope -

i have function reads json document, daynames , monthnames visible outside function, date format isn't. inside function correctly prints value outside doesn't update outside value. why dateformat doesn't update outside function?

var daynames = []; var monthnames = []; var dateformat = ""; $.getjson("/scripts/cldr/main/"+ culture + "/ca-gregorian.json", function (json) {     $.each(json.main.@(system.threading.thread.currentthread.currentculture.name).dates.calendars.gregorian.days.format.short, function (key, val) {         daynames.push(val);     });     $.each(json.main.@(system.threading.thread.currentthread.currentculture.name).dates.calendars.gregorian.months["stand-alone"].wide, function (key, val) {         monthnames.push(val);     });     dateformat = json.main.@(system.threading.thread.currentthread.currentculture.name).dates.calendars.gregorian.dateformats.medium;     console.log(dateformat);  //output: y-mm-dd }); console.log(dateformat); //output:  

the problem $.getjson() asynchronous call. console.log(datefomrat) outside function runs before function finishes. code continues while $.getjson() running dateformat isn't set when second(outside) console.log() executes.