tr = document.createElement("tr");
            td1 = document.createElement("td");
            td2 = document.createElement("td");
            td1.appendChild(document.createTextNode("Number:"));
            td2.appendChild(document.createElement("input"));
            td2.setAttribute("id", "nr");
            tr.appendChild(td1);
            tr.appendChild(td2);
            table.appendChild(tr);

var nr = document.getElementById("nr").value;