Question

var position= $.getJSON( "http://ip-api.com/json", function( data ) {
  position =  {lon: data.lon, lat: data.lat}
  return position;
});
 var lon = position.lon;
 var lat = position.lat;
console.log(lon);

如何从异步函数中获取变量才能变为全局？

Answer 1

试试这个，这是好方法

window.onload = function() {
set();
setTimeout(get,2000);;
};
function set() {
$.getJSON( "http://ip-api.com/json",function(data) {
var position = {"lon": data.lon,"lat": data.lat};
document.getElementById("id").value= position;
});
}
function get() {
var k = $("#id").val();
console.log(k);

}

Answer 2

我明白了。我让ajax函数不像这样异步：

type RawText = String
-- [Char] 'a','b','c','d','e'
type SingleWord = String
type Line = [SingleWord]
type Page = [Line]

--        [-------CHAR-----]
-- split " one two three ff " = ["one","two","three","ff"]
--                              [char],[char],[char],[char]
-- " " is delimiter for a []

split' :: RawText -> [SingleWord]
spilt' [] = []
split' xs
    | xs == [] = []
    | isBlank (head xs) = split' xs
    | otherwise = waitForBlank xs : spilt' (tail xs)

isBlank :: Char -> Bool
isBlank x = if x == ' ' then True else False

waitForBlank :: String -> String
waitForBlank [] = []
waitForBlank (x:xs)
    | isBlank x = []
    | otherwise = x : waitForBlank xs

Answer 3

在声明要成为全局的变量时不要使用var

在全局变量jquery中存储API数据

3 个答案: