var counter = 1; function newliner(){ counter += 1; var child = document.getElementById("sample"); child = child.cloneNode(true); child.id = ""; child.children[0].textContent = counter; child.children[1].children[0].value = ""; child.children[2].children[0].value = ""; child.children[3].children[0].value = 0; document.getElementById("MainTable").appendChild(child); updateaverage(); } function updateaverage(){ var marks = Array.from(document.getElementsByClassName("marks")); var avg = 0; for(var i = 0; i < marks.length; i++){ if(Number(marks[i].value) == 0){ avg += 1 }else{ avg += Number(marks[i].value); } } avg = Math.floor((avg * 100) / marks.length); avg = avg / 100; document.getElementById("average").textContent = `Az átlag: ${avg}`; }