Javascript全局变量仅在匿名函数内更新

Question

please give me some clue for this javascript problem. I have a global variable markers. And try to push every marker to markers. But the problem is , after push to markers. i was trying to alert the value inside function and outside function. the result is totally different. markers inside function give me array of marker, but markers outside stay empty. Why i got different value of markers global variable?

This is the snippet of my code:

for (var i = 0; i < netotal; i++) {
    setTimeout(function () {
        marker = new google.maps.Marker({
            position: pos[iterator],
            map: map,
            draggable: false,
            animation: google.maps.Animation.DROP,
            icon: neicon  
        });
        iterator++;
        markers.push(marker);console.log(markers);
    }, i * 50);  
}

alert (markers);

Thank you for your kind help or clue.

Answer 1

取决于范围，访问全局标记使用window.markers 。

Answer 2

You're pushing to markers in a function that's called using setTimeout , so the push won't happen until some time later. But you're calling alert(markers) immediately, before any of the timeouts have occurred. So the array is empty at that time.

UPDATE:

To see the final contents of markers , you need another setTimeout :

setTimeout(function() { alert(markers); }, netotal*50);