如何使用普通 JavaScript 访问 AJAX 调用中返回的数据？

Question

I wrote my first AJAX call last week and got it to work, but now I'm writing a different AJAX call and need to access the data returned, not just change something onSuccess.

<script type="text/javascript">
    function showMessage(jobid) {
         let result;
         new Request.JSON({
             url: '<?php echo site_url('job/getDiscrepancyByJobId/'); ?>/' + jobid,
             dataType: 'text',
             onSuccess: function(data) {
                 console.log(data);
             }
         }).send();
     }
</script>

When the script above is called, I get nothing output to the console. I tried doing this:

<script type="text/javascript">
    function showMessage(jobid) {
        let request = new XMLHttpRequest();
        request.open('GET', '<?php echo site_url('job/getDiscrepancyByJobId'); ?>/' + jobid, true);
        request.onload = function() {
            if (this.status >= 200 && this.status < 400) {
                console.log('data: ' + JSON.stringify(this.response));
            } else {
                    // Error
            }
        };
        request.send();
    }
</script>

but that just outputs data: "" to the console.

This is the function that is called:

public function getDiscrepancyByJobId($jobid) {
    return $this->MJob->getJobChangeLog($jobid);
}

And MJob->getJobChangeLog($jobid) is:

function getJobChangeLog($jobid, $limit = 10) {
    if (empty($jobid)) {
        return false;
    }
    $Q = $this->read_db->query('select timestamp, ifnull(t.name, ifnull(u.name, "")) as name, uri, description, postdata, marginchange 
         from jobchangelog l 
         left join user u on u.id=l.userid 
         left join transcriber t on t.id=u.transcriberid 
         where jobid=' . intval($jobid) . '
         order by timestamp desc 
         limit ' . intval($limit));
    return array_map(function($a){ $a['postdata'] = @unserialize($a['postdata']); return $a; }, $Q->result_array());
}

The information I'm looking for is in the @unserialize($a['postdata']) part and I don't know how to access that either.

Any help would be great. Thank you in advance for your patience.

Answer 1

I changed the getDiscrepancyByJobId function to this:

public function getDiscrepancyByJobId($jobid) {
    $discrepancy = $this->MJob->getJobChangeLog($jobid);
    echo $discrepancy[0]['postdata']['message'];
}

And I changed the AJAX request to this:

function showMessage(jobid) {
    let request = new XMLHttpRequest();
    let jid = jobid;
    request.open('GET', '<?php echo site_url('job/getDiscrepancyByJobId'); ?>/' + jobid, true);
    request.onload = function() {
        if (this.status >= 200 && this.status < 400) {
             console.log(decodeURIComponent(this.response));
        } else {
             // Error
        }
    };
    request.send();
}

Thanks for the help!