如何在谷歌图表中使用javascript全局变量

Question

我在java脚本中全局定义了变量，并想在谷歌图表中使用它，但它给出了未定义的错误。

var period;
$(document).ready(function () {
$('#period').on('change', function () {
window.period = this.value;
alert(period);
});
// period variable in google chart is showing undefined
google.charts.load('current', {
callback: function drawChart() {
var jsonData = $.ajax({
type: 'GET',
url: "{{ url('/datesalesbarchartdata') }}/" + period ,
dataType: "json",
global: false,
async: false,
success: function (jsondata) {
}
}).responseText;

Answer 1

工作代码

var period;
$('#period').on('change', function () {
window.period = this.value;
google.charts.load('current', {
callback: function drawChart() {
console.log(period);
var jsonData = $.ajax({
type: 'GET',
url: "{{ url('/datesalesbarchartdata') }}/" + period ,
dataType: "json",
global: false,
async: false,
success: function (jsondata) {
}
}).responseText;
});