问我的clearTimeout函数不工作

EN

var timer;

function startTimer(secs, elem) {
    var element = document.getElementById(elem);
    var randomclick = Math.floor(Math.random() * 4 + 1);

    if (secs > 9) {
        element.innerHTML = "0:" + secs;
    } else if (secs > -1) {
        element.innerHTML = "0:0" + secs;
    } else if (secs < -1) {
        clearTimeout(timer);
        alert(randomclick);

        if (randomclick == 1) {
            buttonAPress();
        }
        if (randomclick == 2) {
            buttonBPress();
        }
        if (randomclick == 3) {
            buttonCPress();
        }
        if (randomclick == 4) {
            buttonDPress();
        }
    }

    secs = secs - 1;
    timer = setTimeout(function() {
        startTimer(secs, elem)
    }, 1000);
}

startTimer(10, 'myDiv');

<div id='myDiv'></div>

var timer;    
var el = document.getElementById('el');

function startTimer(secs,elem){
var element = document.getElementById(elem);
var randomclick = Math.floor(Math.random()*4+1);


if (secs > 9){
    element.innerHTML = "0:" + secs;
}
else if (secs > -1){
    element.innerHTML = "0:0" + secs;
}
else if(secs < -1){
    clearTimeout (timer);// `` <============ typo ??
    alert ('randomclick => ' + randomclick + ' \nit works');

    if (randomclick == 1){buttonAPress();}
    if (randomclick == 2){buttonBPress();}
    if (randomclick == 3){buttonCPress();}
    if (randomclick == 4){buttonDPress();}

}
secs--;
timer = setTimeout('startTimer('+secs+',"'+elem+'")',1000);


}
startTimer(12  , 'el')

<div id='el'>p</div>