Javascript make a function read file to an array and return the result to this function

Question

Like as title, i want to make a function read file to an array with passing parameters and return the result to this function. This is my code:

    function getdata(url) {
    var myArr = "";
    var exArr = "";
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
             myArr = xmlhttp.responseText;
        }
    }
    xmlhttp.open("GET", url, true);
    xmlhttp.send();
    exArr = myArr.split('\n');
    return exArr;
    }

    var getit = getdata("http://pastebin.com/raw/BtqPzkHg")
    console.log(getit)

But unfortunately, it's not working and if so, could you give me your ideas, thank you so much