两个数字相加,怎么会得NaN?
//tb.value初始为0
function SetTotal(tb)
{
var total = parseFloat(tb.value);
var tbl = document.getElementById("DataGrid1");
var n = tbl.rows.length;
for (var i=0; i < n; i++)
{
var ck = tbl.rows[i].cells[0].firstChild;
if(ck.checked)
{
alert(parseFloat(tbl.rows[i].cells[6].innerHTML));//这里显示的是数字
total += parseFloat(tbl.rows[i].cells[6].innerHTML);
alert(total);//这里显示的是NaN
}
else
{
total -= parseFloat(tbl.rows[i].cells[6].innerHTML);
}
}
alert(total);
if(total >= 0)
tb.value = total;
else
tb.value = 0;
}