从PHP / SQL获取GET信息的时间

Just for you to know I'm less than a newbie!

I have the following javascript code:

window.onload = function() {
    renderTime();
    getsec(myHandler);
    countdown('countdown');
    ...
}
function myHandler(resultado) {
    seconds = resultado;
}
function reqListener () {
    console.log(this.responseText);
}
function getsec(callback) {
    var indice = 1;
    var oReq = new XMLHttpRequest(); 
    oReq.onload = function() {
        var variarr = JSON.parse(this.responseText);
        callback(variarr[0]);
    };
    oReq.open("GET", "getsec.php?lei="+indice, true);
    oReq.send();
}

This works perfectly for me. The intention is to get data from MySQL table through getsec.php every second. As you can see I have function countdown('countdown') that looks like this:

function countdown(element) {
    ...
    interval = setInterval(function() {
        ...
        if( runned == false){ // This condition happens
            ...
        } else {
            ...
        }
    }, 1000);
}

I tryed to put function getsec(myHandler) inside function countdown('countdown')

        if( runned == false){ // This condition happens
            getsec(myHandler);

and I stop getting the information I want. Can anyone explain me why?