NaN return values here what happen

function calcc() {
       var table = document.getElementById('countTable');
       var   total;
       var arlene1 = [];
       arlene1=document.getElementById('t3').value;
       for (var i = 0; i < table.rows.length; i++) {
           total += +parseFloat(arlene1[i],10);
           alert(total);
        document.getElementById('Text1').value = total;

       }