Only one ajax function is called

Question

I have a personal project which worked well and i want to add a new feature to it by including an ajax function but it looks like it is not called(checkRemaining). I even added the same behaviour as the previous ajax function(start) but still it doesn't execute, only the first one. Both functions call mysql query.

I am a working script which looks like this :

Label("Tx",9,  Tx[0], 10);
Label("Tx",10, Tx[1], 10);
Label("Tx",17, Tx[5], 10);
Label("Tx",18, Tx[2], 10);
Label("Tx",19, Tx[3], 10);
Label("Tx",20, Tx[4], 12);


function Label($ty, $h, $el, $nr){
    var x,remaining;
    x = start($ty,$h);
    remaining = checkRemaining($ty,$h);
    if(x == $nr)
        appendFull($el);
    else{
        $el.addEventListener("click", function(){
            document.getElementById('tipe').value = $ty+ "   " + $h;
            // document.getElementById('loc').value = 'test';
            window.scrollTo(0,document.body.scrollHeight);
            undisableButton();
        });
        appendLabel($el);
    }
}

The working function:

function start(z,o){
    var result =0;
    $.ajax({
        type: "POST",
        url: "CheckDate.php",
        datatype: "html",
        async: false,
        data: {ty: z, h: o},
        success: function(data) {
            result = data;
        }
    });
    return result;
}

The non working function :

function checkRemaining(z,o){
    var result =0;
    $.ajax({
        type: "POST",
        url: "CheckRemaining.php",
        datatype: "html",
        async: false,
        data: {ty: z, h: o},
        success: function(data) {
            result = data;
        }
    });
    return result;
}