不计算每一行网格.net

我遇到麻烦了，请帮忙。我有一个网格，在第一行的网格值计算，但在其他行计算没有任何效果。我在后端使用了数据表。我现在该怎么办?帮助你. .

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Javascript代码

            function CalculateTotal() {
            var Gtot = 0;
            var Participation = document.getElementById('txtCl_Part').value-0;
            var Assgnmnt = document.getElementById('txtAssgnmnt').value-0;
            var Quiz = document.getElementById('txtQuiz').value-0;
            var WrPaper = document.getElementById('txtWP').value-0;
            var OSME = document.getElementById('txtOSME').value-0;
            var Total = parseFloat(Participation) + parseFloat(Assgnmnt) + parseFloat(Quiz) + parseFloat(WrPaper) + parseFloat(OSME);
            if (!isNaN(Total)) {
                document.getElementById('txtTotal').value = Total;
            }
            else {
                alert("Nikal");
            }
            var getTotal = document.getElementById('txtTotal').value - 0;
            var Gtot = parseInt(Gtot) + parseFloat(getTotal);
            if (!isNaN(Gtot)) {
                document.getElementById('txtGTot').value = Gtot;
            }
            else {
                alert("Cannot Show Total");
            }
            var Percentage = (parseFloat(Gtot) * 100) / 400;
            if (!isNaN(Percentage)) {
                document.getElementById('txtPercent').value = Percentage;
            }
            else {
                alert("Cannot show percentage");
            }
        }