How to disable delete button when all the checkboxes are disabled of a column in grid asp.net by JavaScript?

I have a grid in which i have 7 columns where all the checkboxes are disabled. How do I disable the delete button?

In the diagram below, if all the checkboxes in the Cancel SO Line Item column are disabled then the DEL button should be disabled

.Aspx File

<asp:TemplateField HeaderText="Cancel SO Line Item">
        <ItemTemplate>
        <asp:checkbox ID="cbSOCan" runat="server" ViewStateMode="Enabled" EnableViewState="true"></asp:checkbox>
         </ItemTemplate>

     <asp:LinkButton CssClass="btn btn-primary" ID="btnCancelItem" runat="server" CausesValidation="False"OnClientClick="return Confirmationbox();">&nbsp;Cancel Item</asp:LinkButton>
 <asp:HiddenField id="hdnval" value=0 runat="server"/>

C# code

protected void btnCancelItem_Click(object sender, EventArgs e)
{
    foreach (GridViewRow gvrow in gvPOItems.Rows) {
        CheckBox chkdelte = (CheckBox)gvrow.FindControl("cbSOCan");
        HiddenField hdnval = (HiddenField)gvrow.FindControl("hdnval");
        if (chkdelte.Checked) {
            // gvAdditionalArea.Rows(rowIndex).Cells(0).Text()
            Int32 ItemNumber = Convert.ToInt32(gvrow.Cells(0).Text());
            Queries.CancelSOlineItem(ItemNumber, txtPONumber.Text);
            gvrow.Cells(7).Text() = "Cancelled";
            chkdelte.Checked = false;
            chkdelte.Enabled = false;
            hdnval.Value = 1;
}
}
protected void Page_Load(object sender, EventArgs e)
{
{if (!IsPostBack)
int rowcount = 0;
foreach (GridViewRow gvrow in gvPOItems.Rows) {
    HiddenField hdnval = (HiddenField)gvrow.FindControl("hdnval");
    if ((hdnval.Value == 1)) {
        rowcount = rowcount + 1;
    }
}
if ((gvPOItems.Rows.Count == rowcount)) {
    btnCancelItem.Visible = false;
}
}
}