是因为captureVisibleTab()返回promise,并且具有(数据)的函数在captureVisibleTab()的函数内部吗?我该如何从captureVisibleTab()中获取base64?
var base64; //global variable
browser.tabs.captureVisibleTab(null, {}, function (data) {
base64 = data; //this contains base64
console.log(base64); //this prints out base64 code
});
console.log(base64); //but this is undefined