navigator.geolocation错误函数触发两次

Question

我正在请求我的用户使用以下功能从浏览器获取他们的位置：

if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(set_map_location,geoloc_error,{
        enableHighAccuracy:false,
        maximumAge:85000,
        timeout:15000
    });
}

如果出现问题或进程超时，我的geoloc_err函数会被调用：

function geoloc_error(err) {
    if (err.code == 1) {
        alert("You denied the browser access to your location."
        + "\nYou can find your position manually by dragging the map and zooming in/out.");
    } else if (err.code == 2) {
        alert("The geolocation network is not available or your position could not be found."
        + "\nYou can find your position manually by dragging the map and zooming in/out.");
    } else {
        alert("The browser took too long to find your location. Trying again can sometimes yield different results.\n"
        + "You can find your position manually by dragging the map and zooming in/out.");
    }
}

现在，有时会发生错误，例如err.code==2 the network was unavailable，并且会弹出警告并警告我。问题是，几秒钟后，另一个警告框警告我该过程也已超时。

我的问题是，如何停止发生第二次错误警告？我无法退出该函数，因为正在从第一个函数调用错误。