php and javascript checkbox conflict

sam · June 8th, 2004, 04:04 PM

I created a page which creates an array of checkbox values:

Code:

<tr valign="top"> 
  <td width="230" class="newstext">
      <input name="checkbox[]" type="checkbox" class="form_white" value="Awarness Program for one month $900.00">
      <span class="newstext">One Month $900</span><br> 
      <input name="checkbox[]" type="checkbox" class="form_white" value="Awarness Program for one one week $225.00">
      <span class="newstext">One Week $225</span>
  </td>
  <td>
      <input name="checkbox[]" type="checkbox" class="form_white" value="Keep the Health Hotline running for one week $350.00">
      <span class="newstext">One Week $350</span><br> 
      <input name="checkbox[]" type="checkbox" class="form_white" value="Keep the Health Hotline running for one day $50.00">
      <span class="newstext">One Day $50</span> 
  </td>
</tr>

my problem occurred when I wanted to check on the client side if any thing was checked off both

Code:

      var boxct = document.form1.checkbox.length
      var bCB = false
      for(var ct=0; ct < boxct; ct++)
        {
            if(document.form1.checkbox[ct].checked)
                {
                    bCB = true;
                }
        }

and

Code:

      var boxct = document.form1.checkbox[].length
      var bCB = false
      for(var ct=0; ct < boxct; ct++)
        {
            if(document.form1.checkbox[][ct].checked)
                {
                    bCB = true;
                }
        }

got an error.
How does one deal with this?
Thanks,
Sam

Snib · June 8th, 2004, 04:28 PM

Find and Replace all 'checkbox' with 'elements' and I think it will work.

Snib

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sam · June 8th, 2004, 05:06 PM

>Find and Replace all 'checkbox' with 'elements' and I think it will work.

not following what you mean do you mean
name="elements[]"
var boxct = document.form1.elements[].length?
thanks,
sam

richard.york · June 8th, 2004, 05:28 PM

Checkboxes aren't arrays on the client-side the empty bracket syntax will create an array on the server-side, but with JS you have to take a different approach since JS will only access a checkbox individually.

One way of handling this is to fill in the numbers

<input name="checkbox[0]"...

<input name="checkbox[1]"...

<input name="checkbox[2]"...

And then modify your JS code accordingly, you have to reference the checkbox by its name specifically. Don't remember the JS syntax but maybe something like this:

if (document.getElementsByName('checkbox[' + counter + ']').checked == TRUE)
{
...

HTH!

Regards,
Rich

::::::::::::::::::::::::::::::::::::::::::
The Spicy Peanut Project
http://www.spicypeanut.net
::::::::::::::::::::::::::::::::::::::::::

Snib · June 8th, 2004, 05:41 PM

I'm not sure if what you're talking about will work, Rich. I have never heard of getElementsById.

What I was saying was to modify the code like so:

      var boxct = document.form1.elements.length;
      var bCB = false;
      for(var ct=0; ct < boxct; ct++)
        {
            if(document.form1.elements[ct].checked)
                {
                    bCB = true;
                }
        }

Snib

<><

sam · June 8th, 2004, 05:50 PM

thanks Snib it worked:

Code:

      var boxct = document.form1.elements.length
      var bCB = false
      for(var ct=0; ct < boxct; ct++)
        {
            if(document.form1.elements[ct].checked && document.form1.elements[ct].type == 'checkbox')
                {
                                        bCB = true;
                }
        }

Thanks.

richard.york · June 8th, 2004, 06:01 PM

I used 'getElementsByName' and not 'getElementsById' and just because you haven't heard of it doesn't mean it won't work ;). getElementsByName looks at the 'name' attribute to access the element.

Re: the elements property.
To get around possible conflicts with other checkboxes (not related to those you want to access) I would also check that the checkbox name is 'checkbox[]'.

Regards,
Rich

::::::::::::::::::::::::::::::::::::::::::
The Spicy Peanut Project
http://www.spicypeanut.net
::::::::::::::::::::::::::::::::::::::::::

Snib · June 8th, 2004, 06:06 PM

Rich:

Sorry, I misread your code. I've been making mistakes like this all day

Anyway like you said, I would check if the name is "checkbox[]" or that the type is "checkbox", if some have a different name.

HTH,

Snib

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