是php json_encode和AJAX打破我的阵列？

Question

I'm grabbing some database entries, creating a 2D array and then passing them to js with AJAX. But when I loop through the array in javascript, it's an "undefined" mess. The console log for dbArray works fine, so I know the PHP/AJAX is working. Not sure what I am doing wrong with the loop...

PHP ('load-words.php):

$query = mysql_query("
SELECT * FROM words 
ORDER BY RAND() 
LIMIT 50
") or die(mysql_error()); 

$dbArray = array(); 
while ($row = mysql_fetch_assoc($query)) {
    $word_phrase = stripslashes($row['word_phrase']);
    $description = stripslashes($row['description']);
    // construct a 2D array containing each word and description
    $dbArray[] = array($word_phrase,$description);      
};

echo json_encode($dbArray);

Javascript:

$.ajax({
    url: 'func/load-words.php',
    success: function(dbArray) {
        console.log(dbArray);
        var items = "<ul>";
        for (var i in dbArray) {
            items += "<li><a href='#'><b>" + dbArray[i][0] + ' : ' + dbArray[i][1] + "</a></li>";
        }
        items += "</ul>";
        div = $('#dbArray');
        div.html(items);
    }
});

Answer 1

I guess this is failing because jQuery is interpreting the AJAX response as a string, since your PHP is not outputting a JSON header and your AJAX is not stipulating JSON. This is easily tested:

$.ajax({
    url: 'func/load-words.php',
    success: function(dbArray) { alert(typeof dbArray); /* "string"? */ }
});

Try

$.ajax({
    url: 'func/load-words.php',
    dataType: 'json', //<-- now we explicitly expect JSON
    success: function(dbArray) { alert(typeof dbArray); /* "object"? */ }
});