Problem with validating checkbox array

[frankiehots]

I am trying to use JavaScript to require that at least one one checkbox of multiple checkbox choices is selected. My validation works except that I need to add a "[]" to the checkbox name for separate server processing. Once I do that, my validation no longer works.

Here is my code:

  <script type="text/javascript">
  function formValidate(){
     with(document.checkboxform){
  			  checkSelected = false;
  			  for (i=0;  i < infocheckbox[].length;  i++)	{
  				   if (infocheckbox[][i].checked){
  				   checkSchool = true;
  			   }
  		 if (!checkSelected){
  				alert('Please choose at least one checkbox');
  				return false;
  			} 
  		else {
  			return true;
  			}
  
    } 	 
  }
</script>

When I use infocheckbox[] the validation does not work, but if I remove the [] and just use infocheckbox, it works just fine. Any idea on what I need to do to be able to use []?

[chris_fuel]

My validation works except that I need to add a "[]" to the checkbox name for separate server processing.

Can you expand on that a bit? What does your server processing need to do that requires the [] be present in the javascript?

[frankiehots]

Can you expand on that a bit? What does your server processing need to do that requires the [] be present in the javascript?

Sorry for not providing enough info. I am using PHP to detect for the presence of an array and the [] is typically how I've done it in HTML forms. For example:

 <input type="checkbox" name="infocheckbox[]" value="red">Red
 <input type="checkbox" name="infocheckbox[]" value="blue">Blue
 <input type="checkbox" name="infocheckbox[]" value="green">Green
 <input type="checkbox" name="infocheckbox[]" value="purple">Purple

By using the "[]", PHP sees an array (is_array) and then can handle it differently than other form POST variables.

[chris_fuel]

Hi,

have you tried this:

  			  for (i=0;  i < infocheckbox.length;  i++)	{
  				   if (infocheckbox[i].checked)

?

[JVLB]

JavaScript doesn't automatically assemble an array from the elements using the PHP name convention you mention. You'll have to create your own array with:

document.getElementsByName('infobox[]')

Assign the output to a variable and it will provide you a 0-based array with which to access the elements.

[frankiehots]

JavaScript doesn't automatically assemble an array from the elements using the PHP name convention you mention. You'll have to create your own array with:

document.getElementsByName('infobox[]')

Assign the output to a variable and it will provide you a 0-based array with which to access the elements.

Perfect solution JVLB, thanks a lot. That will come in handy for the future too.