pingu,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<div data-umnozenie="19,16,15.5,6,3.5,1.5,0.7,0.5,0.02" class="umnozenie pozitiv">
<div class="umnozenie">Pozitiv</div>
<div data-multiple="444" class="umnozenie">444</div>
<div data-multiple="55" class="umnozenie">55</div>
<div data-multiple="15.5" class="umnozenie">15.5</div>
<div data-multiple="6" class="umnozenie">6</div>
<div data-multiple="3.5" class="umnozenie">3.5</div>
<div data-multiple="1.5" class="umnozenie">1.5</div>
<div data-multiple="0.7" class="umnozenie">0.7</div>
<div data-multiple="0.5" class="umnozenie">0.5</div>
<div data-multiple="0.22" class="umnozenie">0.02</div>
</div>
<script>
alert(document.querySelector('[data-umnozenie]').dataset.umnozenie.split(','));
</script>
</body>
</html>