My arrow key are not responding when i press arrow row or any arrows in does not respondUnhandled exception at line 24 column 19 in httpslocalhost44371FormsClassinterview0x800a138f JavaScript runtime error Unable to get property 39length39 of undefined or null referenceat lineif trrowIndex lt trparentNoderowslength 1my codelt Page Language34vb34 AutoEventWireup34false34 CodeBehind34Classinterviewaspxvb34 Inherits34INTERVIEWSVBClassinterv

makumbi saysltscript typetextjavascriptgt function enterobj var tr objparentNodeparentNode if eventkeyCode 40 Down if trrowIndex lt trparentNoderowslength 1 trparentNoderowstrrowIndex 1cellsobjparentNodecellIndexchildren0focus return if eventkeyCode 37 Left if objparentNodecellIndex gt 0 trparentNoderowstrrowIndexcellsobjparentNodecellIndex 1children0focus return if eventkeyCode 39 Right if objparentNodecellIndex lt trcellslength 1 trparentNoderowstrrowIndexcellsobjparentNodecellIndex 1children0focus return if eventkeyCode 38 Up if trrowIn

[Solved] JavaScript Error: Unable to get property length of undefined or null reference

makumbi

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User: makumbi
Posted: on Mar 14, 2022 01:40 AM
Forum: JavaScript
Answer: 1
Views: 2933

My arrow key are not responding when i press arrow row or any arrows in does not respond.

Unhandled exception at line 24, column 19 in https://localhost:44371/Forms/Classinterview
0x800a138f - JavaScript runtime error: Unable to get property 'length' of undefined or null reference

at line

if (tr.rowIndex < tr.parentNode.rows.length - 1)

my code

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Classinterview.aspx.vb" Inherits="INTERVIEWSVB.Classinterview" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">
        function askConfirm(msg) {
            alert(msg)
        }
    </script>

    <script type="text/javascript">
        function enter(obj) {
            var tr = obj.parentNode.parentNode;
            if (event.keyCode == 40) //Down
            {
                if (tr.rowIndex < tr.parentNode.rows.length - 1)
                    tr.parentNode.rows[tr.rowIndex + 1].cells[obj.parentNode.cellIndex].children[0].focus();
                return;
            }
            if (event.keyCode == 37) //Left
            {
                if (obj.parentNode.cellIndex > 0)
                    tr.parentNode.rows[tr.rowIndex].cells[obj.parentNode.cellIndex - 1].children[0].focus();
                return;

            }
            if (event.keyCode == 39) //Right
            {
                if (obj.parentNode.cellIndex < tr.cells.length - 1)
                    tr.parentNode.rows[tr.rowIndex].cells[obj.parentNode.cellIndex + 1].children[0].focus();
                return;

            }
            if (event.keyCode == 38) //Up
            {
                if (tr.rowIndex > 1)
                    tr.parentNode.rows[tr.rowIndex - 1].cells[obj.parentNode.cellIndex].children[0].focus();
                return;
            }
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">            <
                <table class="auto-style2">
                    <tr>
                        <td>
                            <asp:GridView ID="GvStudentMarks" runat="server" AutoGenerateColumns="False" OnRowDataBound="gvStudentMarks_RowDataBound" AllowPaging="True" PageSize="20">
                                <Columns>
                                    <asp:TemplateField>
                                        <HeaderTemplate>
                                            <asp:CheckBox ID="chkAll" runat="server" AutoPostBack="true" />
                                        </HeaderTemplate>
                                        <ItemTemplate>
                                            <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="true" />
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Account">
                                        <EditItemTemplate>
                                            <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Account") %>'></asp:TextBox>
                                        </EditItemTemplate>
                                        <ItemTemplate>
                                            <asp:Label ID="Label6" runat="server" Text='<%# Bind("Account") %>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Name">
                                        <EditItemTemplate>
                                            <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Name") %>'></asp:TextBox>
                                        </EditItemTemplate>
                                        <ItemTemplate>
                                            <asp:Label ID="Label3" runat="server" Text='<%# Bind("Name") %>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Category">
                                        <EditItemTemplate>
                                            <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Category") %>'></asp:TextBox>
                                        </EditItemTemplate>
                                        <ItemTemplate>
                                            <asp:Label ID="Label4" runat="server" Text='<%# Bind("Category") %>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Stream">
                                        <EditItemTemplate>
                                            <asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("Stream") %>'></asp:TextBox>
                                        </EditItemTemplate>
                                        <ItemTemplate>
                                            <asp:Label ID="Label5" runat="server" Text='<%# Bind("Stream") %>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Eng">
                                        <ItemTemplate>
                                            <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                                                <ContentTemplate>
                                                    <asp:Label ID="lblEng" runat="server" Text='<%# Eval("Eng") %>' Visible="False"></asp:Label>
                                                    <asp:TextBox ID="TxtEng" runat="server" OnTextChanged="txtEng_TextChanged" Text='<%# Eval("Eng") %>' onkeyup="enter(this)" AutoPostBack="True" Height="16px" Width="58px" onchange="return GetSelectedRow(this)"></asp:TextBox>
                                                    <asp:RangeValidator ID="RangeValidator1" runat="server" BackColor="#FF99FF" ControlToValidate="TxtEng" Display="Dynamic" ErrorMessage="Invalid" MaximumValue="100" MinimumValue="0" SetFocusOnError="True" Type="Double"></asp:RangeValidator>
                                                </ContentTemplate>
                                            </asp:UpdatePanel>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Maths">
                                        <ItemTemplate>
                                            <asp:UpdatePanel ID="UpdatePanel2" runat="server">
                                                <ContentTemplate>
                                                    <asp:Label ID="lblMaths" runat="server" Text='<%# Eval("Maths") %>' Visible="False"></asp:Label>
                                                    <asp:TextBox ID="TxtMaths" runat="server" OnTextChanged="txtMaths_TextChanged" Text='<%# Eval("Maths") %>' onkeyup="enter(this)" AutoPostBack="True" Width="48px" onchange="return GetSelectedRow(this)"></asp:TextBox>
                                                    <asp:RangeValidator ID="RangeValidator2" runat="server" BackColor="#FF99FF" ControlToValidate="TxtMaths" Display="Dynamic" ErrorMessage="Invalid" MaximumValue="100" MinimumValue="0" SetFocusOnError="True" Type="Double"></asp:RangeValidator>
                                                </ContentTemplate>
                                            </asp:UpdatePanel>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="TotalMarks">
                                        <ItemTemplate>
                                            <asp:Label ID="lblTotalMarks" runat="server" Text='<%# Eval("avgs") %>' Visible="False"></asp:Label>
                                            <asp:TextBox ID="txtTotalmarks" runat="server" Text='<%# Eval("Avgs") %>' ReadOnly="True" Width="49px"></asp:TextBox>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Average">
                                        <ItemTemplate>
                                            <asp:TextBox ID="txtAverage" runat="server" Text='<%# Eval("Avgs2") %>' ReadOnly="True" Width="48px"></asp:TextBox>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:BoundField HeaderText="Sst" DataField="Sst" />
                                    <asp:BoundField DataField="Science" HeaderText="Science" />
                                    <asp:TemplateField HeaderText="Entered Date">
                                        <EditItemTemplate>
                                            <asp:TextBox ID="Entrydate" runat="server" Text='<%# Bind("emarksdate") %>'></asp:TextBox>
                                        </EditItemTemplate>
                                        <ItemTemplate>
                                            <asp:Label ID="Label1" runat="server" Text='<%# Bind("emarksdate") %>'></asp:Label>
                                            <asp:TextBox ID="Entrydates" runat="server" Text='<%# Eval("emarksdate") %>'></asp:TextBox>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                </Columns>
                            </asp:GridView>
                        </td>
                    </tr>
                </table>
            </div>
            <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="False">
            </asp:ScriptManager>
    </form>
</body>
</html>

arjunv

0 3

Reply
ANSWER
User: arjunv
Replied: on Mar 15, 2022 03:05 AM
Report

makumbi says:
<script type="text/javascript">

        function enter(obj) {

            var tr = obj.parentNode.parentNode;

            if (event.keyCode == 40) //Down

            {

                if (tr.rowIndex < tr.parentNode.rows.length - 1)

                    tr.parentNode.rows[tr.rowIndex + 1].cells[obj.parentNode.cellIndex].children[0].focus();

                return;

            }

            if (event.keyCode == 37) //Left

            {

                if (obj.parentNode.cellIndex > 0)

                    tr.parentNode.rows[tr.rowIndex].cells[obj.parentNode.cellIndex - 1].children[0].focus();

                return;

            }

            if (event.keyCode == 39) //Right

            {

                if (obj.parentNode.cellIndex < tr.cells.length - 1)

                    tr.parentNode.rows[tr.rowIndex].cells[obj.parentNode.cellIndex + 1].children[0].focus();

                return;

            }

            if (event.keyCode == 38) //Up

            {

                if (tr.rowIndex > 1)

                    tr.parentNode.rows[tr.rowIndex - 1].cells[obj.parentNode.cellIndex].children[0].focus();

                return;

            }

        }

    </script>

Please replace above JavaScript code with below modified code.

<script type="text/javascript">
    function enter(obj) {
        var tr = obj.parentNode.parentNode.parentNode;
        var cellIndex = obj.parentNode.parentNode.cellIndex;
        if (event.keyCode == 37) //Left
        {
            if (cellIndex > 0)
                tr.parentNode.rows[tr.rowIndex].cells[cellIndex - 1].children[0].focus();
            return;
        }
        if (event.keyCode == 38) //Up
        {
            if (tr.rowIndex > 1)
                tr.parentNode.rows[tr.rowIndex - 1].cells[cellIndex].children[0].focus();
            return;
        }
        if (event.keyCode == 39) //Right
        {
            if (cellIndex < tr.cells.length - 1)
                tr.parentNode.rows[tr.rowIndex].cells[cellIndex + 1].children[0].focus();
            return;
        }
        if (event.keyCode == 40) //Down
        {
            if (tr.rowIndex < tr.parentNode.rows.length - 1)
                tr.parentNode.rows[tr.rowIndex + 1].cells[cellIndex].children[0].focus();
            return;
        }
    }
</script>

[Solved] JavaScript Error: Unable to get property length of undefined or null reference

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