JS：遍历URL数组，并在出现任何错误时发出警报

Question

I have an associative array of URL's, each with a unique identifier that i want to iterate through and whichever URL throws a 401 i'd like to set an alert of that specific url's identifier. I'm stuck at the alerting portion:

   for (var i=0; i<lyrs.length; i++){
        $.ajax({
            url: lyrs[i],
            dataType: 'json',
            statusCode: {
                401: function(){
                    console.log('there was a 401 error on something');
                }
            }
        });            
    }

Answer 1

Use a closure:

for (var i=0; i<lyrs.length; i++){
        (function() {
             var url=lyrs[i];
             $.ajax({
                 url: url,
                 dataType: 'json',
                 statusCode: {
                     401: function(){
                         console.log('there was a 401 error on '+url);
                     }
                 }
             });
        })();          
    }

Answer 2

As described in the docs , the function that you associate with 401 can take the same arguments that the error callback. Thus, you can write:

. . .
statusCode: {
    401: function(jqXHR, textStatus, errorThrown) {
        // alert with the specific details
    }
}