Question

This is my $.ajax function. volunteerDist is an array in a previous function and it calls myAjax(volunteerDis);However, the program always calls the error and complete functions, with an error message of undefined. What should I do? Thanks

admin-view-available-volunteeers.php is the filename where this is located
volunteerDist is an array that contains floats

function myAjax(volunteerDist){
        $.ajax({
            type:'POST',
            url: 'admin-view-available-volunteeers.php',
            data : ({
                    distance:volunteerDist
                    }),
            success: function(){
                 alert('worked');
                },
           error :function(err){ 
                    alert('nope :( ERROR: ' + err.ErrorMessage);
                },
           complete : function(){
                       alert('thanks');
           }
        });
}

Answer 1

To get better debugging on error you need to update your code, this

error :function(err){ 
    alert('nope :( ERROR: ' + err.ErrorMessage);
},

will not work – as err is a jqXHR object!

change it to this :

error: function(jqXHR, textStatus, errorThrown) {
   alert("Error : " + errorThrown);
}

This will output the message sent by the server.

All the details for the params of .ajax() are documentation here

Update

Check the name of your PHP file …

admin-view-available-volunteeers.php 

has 3 es in the word volunteer … is this the problem ?