addEventListener should run constantly a function to get width of an object

When you click on the rectangle, it shrinks to become a logo. Now I want to unhide the content div when the welcome div is at ~75px width. I can't figure it out how to contantly run a function when you click the mousebutton.

Please help

html

<div id="introscreen">
    <div id="welcome"></div>
    <p id="help">Zum beginnen auf Rechteck klicken und halten</p>
</div>
<div class="content">
    <header>
        <p id="line">HALLOHALLO</p>
    </header>
</div>

javascript

var counter = 0;
document.addEventListener("click", function () {
    counter++;
    check();
    console.log(counter);
}, false);

function check() {
    if (counter > 5) {
        document.getElementById("help").style.opacity = '1.00';
    }
}
document.addEventListener("mousedown", fadeAway, false);
document.addEventListener("click", showContent, false);

function fadeAway() {
    document.getElementById("help").style.opacity = '0.00';
    var position = $("#welcome").css("width");
    console.log(position);
}

JSFIDDLE