使用PHP进行数据库更新后，no-jquery ajax更新视图

I learn MVC and Ajax, by building a site in PHP and MySQL. I made a new controller method to handle ajax, and am now able to update the database successfully from my Ajax HTTPRequest. When I get the response, i am able to update the division by replacing the current contents of the division with a javascript string like "Hello", but I can't figure out how to replace the contents with my updated database data. How do I update the division correctly? For now I want to do it without JQuery, and am not using a PHP framework. The data in the division is a list of places a member has been. Before Ajax, the list was sent to the "view" when the page loaded:

//this is controller->index()
public function index() {
    //the properties will be pulled up from the db as neccessary so we need to set them first
    $this->member->setMembername();
    $this->member->setMemberProfile();
    $this->member->setMyPlacesList();
    $this->member->setMemberData(); //puts the above data into one array for convenience
    $this->view->setData($this->member->getmemberData());
    $this->view->render('welcomepage/index'); //builds the view with the data
}

Now in my ajax call, my controller tells the member model to update the list of places the member has been:

public function AjaxAddVisit() {
    $details['sitename'] = $_POST["sitename"];
    $details['datetime'] = date("Y-m-d H:i:s");
    $details['comments'] = $_POST['comments'];
    $this->member->addMemberVisit($details); This successfully adds the place to the database.  
    //I suppose I should now do something like ?
    //$this->member->setMyPlacesList();
    //$this->member->setMemberData();
    //$this->view->setData($this->member->getmemberData());//this would update the views data
}

I now want to modify the list in the view from the Ajax code but don't know how, do I do something like the following, where I just embed php code in a javascript string like this?:

function AddVisitResponse() {
    if (myReq.readyState == 4) {
        if(myReq.status == 200) {
        var phpString = "<?php echo $this->data['myPlacesList'][0][1] ?>";
        document.getElementById('myPlacesList').innerHTML = phpString;
        //this would just print out one element of the list, but just for example
        } else {
        alert("got no response from the server");
        }
    }
} 

The output of the above is something like: myPlacesList'][0][1] ?> So i think there must be something wrong. It seems I can't send back a string with php code at all, even when I echo "hello" it doesn't work. How do I update the division correctly? should I format the string in my php controller method using XML? Thank you very much, this is my first question here, and any help would be greatly appreciated!!!

It's hard to tell without seeing the complete ajax code (what's the scope of your myReq variable?), but whatever gets sent back from the server to your ajax script, should be accessible through myReq.responseText.

So you would need to modify your function to:

function AddVisitResponse() {
    if (myReq.readyState == 4) {
        if(myReq.status == 200) {
            document.getElementById('myPlacesList').innerHTML = myReq.responseText;
        } else {
            alert("got no response from the server");
        }
    }
}

Note that any php you include in the javascript on page-load, is already processed by the time you run your javascript function.