values not updated after an ajax response

Pass the result as parameter to updatechart()

$.ajax
({
    type: "POST",
    url: "",
    data: $("form").serialize(),
    success: function(result)
    {
        updatechart(result);      
    }
}); 

then access the results via parameter.

function updatechart(result) {
//.......
//.......
console.log(result);
}

Hope you’re trying something like this.