Why is this javascript loop for checking checkbox values not working?

Jordan Johnson
Jordan Johnson used Ask the Experts™
on
The following form submission function in JavaScript will get the first check box value, but will fail to get others. I have tested this numerous ways, and it seems to always have an issue when getting the ".checked" value for the check box the second time.

Javascript:
function checkForm()
{
  numrows = document.theform.numrows.value;
  if(numrows == -1)
  {
    alert("You do not have any transactions setup yet");
    return false;
  }

  emailcheckcount = 0;
  for(i=0; i<=numrows; i++)
  {
      var recid = document.forms["theform"]["recid"+i].value;
      var checkbox = document.getElementById(recid+"_to"+i);

      if (checkbox.checked)
      {
      emailcheckcount++;

      }
  }

    if(emailcheckcount == 0) {
    alert("Please Select At Least One Email for Alerts");
    return false;
    }

  document.theform.submit();
}

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HTML/ASP:

<%
    numrows = -1
    strSQL = "select recid, customer, documenttpid, tolist, cclist, bcclist, receivedvia, addmailout, emailsubject from MailOut where customer like '%"&cname&"%' and (receivedvia = 'email' or addmailout = 'email') and emailsubject <> 'ignore' order by customer, documenttpid;"
    Set rs = objConnection2.Execute(strSQL, ,adCmdText)
    if not (rs.eof and rs.bof) Then

      arr = rs.getrows()
      numrows = ubound(arr,2)
      for i=0 to numrows
        dim tolist
        dim cclist

        recid = arr(0,i)
        customer = arr(1,i)
        documenttpid = arr(2,i)
        if not IsNull(arr(3,i)) Then
          tolist = split(arr(3,i),"|")
        else
          tolist = null
        end if


        if not IsNull(arr(4,i)) and Len(arr(4,i)) > 0 Then
          cclist = split(arr(4,i),"|")
        else
          cclist = null
        end if

        bcclist = arr(5,i)
        receivedvia = arr(6,i)
        addmailout = arr(7,i)
        emailsubject = arr(8,i)


    %>
    <tr>
    <!--
    <td valign='top' style="border-bottom:1px solid black;">&nbsp;<%=customer%></td>
    <td valign='top' style="border-bottom:1px solid black;">&nbsp;<%=receivedvia%></td>
    -->
    <td valign='top' style="border-bottom:1px solid black;">&nbsp;<%=documenttpid%></td>
    <td valign='top' style="border-bottom:1px solid black;">
    <input type="hidden" name="recid<%=i%>" value="<%=recid%>">&nbsp;<%=emailsubject%></td>
    <td valign='top' style="border-bottom:1px solid black;">
    <%
    emailnum = 0
    if not isNULL(tolist) then
        for each email in tolist
          if  not(isNULL(email) or trim(email)="") Then
    %>
      <input type='checkbox' id='<%=recid%>_to<%=emailnum%>' name='<%=recid%>_to<%=emailnum%>'>&nbsp;<%=email%> /<%=recid%>_to<%=emailnum%>
      <input type='hidden' name='<%=recid%>_to<%=emailnum%>email' value='<%=email%>'><BR>
    <%
          end if

          emailnum = emailnum + 1
        next
    end if
    %>
    <input type='hidden' name='numtoemails<%=i%>' value='<%=emailnum%>'>

    <BR>Add Email:<input type='text' name='addtoemail<%=i%>'></td>
    <td valign='top' style="border-bottom:1px solid black;">
    <%
    ccnum = 0
    if(not isNULL(cclist))then
        for each email in cclist
          if trim(email) <> "") = 0 Then
    %>
      <input type='checkbox' name='<%=recid%>_cc<%=ccnum%>'>&nbsp;<%=email%>
      <input type='hidden' name='<%=recid%>_cc<%=ccnum%>email' value='<%=email%>'><BR>
    <%
          end if

          ccnum = ccnum + 1
        next
    end if
    %>
    <input type='hidden' name='numccemails<%=i%>' value='<%=ccnum%>'>

    <BR>Add Email:<input type='text' name='addccemail<%=i%>'></td>
    </tr>
    <%
      next
    end if
    %>

    <input type="hidden" name="numrows" value="<%=numrows%>">

    <tr><td align="Right" colspan="4"><input type="button" value="Submit" style="width:70px;" class="btn-primary" onclick="checkForm();"></td></tr>

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Top Expert 2015
Commented:
The javascript you posted has nothing to do with the question from what I can see. In that, you are simply counting the number of checked boxes to see if at least one is checked.

In the HTML/ASP script it appears that you are creating a number of checkboxes.

<input type='checkbox' id='<%=recid%>_to<%=emailnum%>' name='<%=recid%>_to<%=emailnum%>'>&nbsp;<%=email%> /<%=recid%>_to<%=emailnum%>

As long as the checkbox names are unique, the post data should include each checked checkbox.

Have you looked at the source code of the rendered page to see if they are indeed unique?

The alternative, if the names are not unique, is to post an array of checked boxes on submit. Add a "[]" to the end of the name.
Most Valuable Expert 2017
Distinguished Expert 2018
Commented:
@Tom
Slight correction
As long as the checkbox names are unique, the post data should include each checked checkbox.
Only the checked items are submitted.

@Jordon, can you show us what the rendered html looks like. I understand what you are trying to do but there are potentially easier ways of doing it for instance with jQuery you can do something like this
$(function() {
  $('form').submit(function() {
    if ($('input:checked').length == 0) {
      alert("Please Select At Least One Email for Alerts");
      return false;
    }
}

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Top Expert 2015

Commented:
@julian - You quoted me but misread. "Post data will include each checked checkbox", meaning "not all the checkboxes", just the checked ones.
Most Valuable Expert 2017
Distinguished Expert 2018

Commented:
@Tommy (blush) apologies - you are 100% correct missed the 'checked'
Most Valuable Expert 2017
Distinguished Expert 2018

Commented:
@Jordon - you have given a B grade on this question without supplying a reason for doing so. Please refer to the EE guidelines on grading.
http://support.experts-exchange.com/customer/portal/articles/481419

By default an A grade is given. Refer to the guidelines for more info

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