checked no matter if value="" (is empty) in array of input checkboxes

Question

Yup. This one is tearing me up. I found a lot of tutorials on this specific subject, but nothing seems to be working for me. I must be missing something which I cannot find.

I am simply trying to keep selected checkboxes checked if there is a previous error in the form. My validation is working totally fine with all fields, but I need to retain the checked boxes and I just can't solve this.

Here are the snippets I am working with:

This checks if the $data[id] isset()

<input name="seminar[]" type="checkbox" id="seminar[]" 
value="
<?php
if(isset($data['id'])) {
         $checked = "checked=\"checked\"";
      } else {

        echo "";
      }
?>
" <?php echo "$checked"; ?>>

And I even checked in my html source, and this is what is showing after submission:

<input name="seminar[]" type="checkbox" id="seminar[]" value="" checked="checked">

As you can see value="" is empty!, so in my script above it should echo "", but that's not working.

As a matter of fact, when I clear the cache and reload the form all boxes are just checked!?

Can anyone see what I am doing wrong. Maybe I am turning over the wrong stones here.. Dunno, but nearly 4 hours down the drain and I'm waiving a white flag.

php code is not showing. I guess its a moderated thing here : ) — OldWest
– OldWest, Commented Jan 17, 2011 at 20:32
You need to select the PHP and click the {} button to make it show properly. — crimson_penguin
– crimson_penguin, Commented Jan 17, 2011 at 20:33
I just fixed it up. In order for code to show up, you need to just indent it by four spaces. — Paul Fisher
– Paul Fisher, Commented Jan 17, 2011 at 20:34
@OldWest: I hope it is fixed now and didn't omit anything. crimson_penguin is right on how to format it. — VoodooChild
– VoodooChild, Commented Jan 17, 2011 at 20:35
Sorry, what? PHP is doing things right. What do you expect PHP to output? Based on the output, $data['id'] is set and then value will be outputted "" and it will be checked. — sh03
– sh03, Commented Jan 17, 2011 at 20:36

Michael Irigoyen · Accepted Answer · 2011-01-17 20:45:50Z

3

I see several things wrong that could possibly be contributing to your problem.

First, you're assigned the name of the checkbox seminar[]. This creates an array with values from all checkboxes that use that name. Since you're not specifying a key in between the [], it automatically does this for you. You should specify some sort of key yourself so you can match them up later.

Example:

<input type="checkbox" name="seminar[0]" id="seminar_0" value="" />

Then you can check if it's set by doing this:

if(isset($_POST['seminiar'][0])) {
  echo "checked=\"checked\"";
}

Second, you can't use seminar[] for the ID of the checkbox. Look at my above example for an alternative way you can do it. IDs have to be unique on the page; You cannot use the same ID twice on a single page.

Third, what is this $data['id'] exactly? You should be checking the $_POST value for the exact name of the item. Again, look at my first example.

I'd reformat your code to look something like this:

$checkboxes = array(0 => "Value 1", 1 => "Value 2", 2 => "Value 3");
foreach($checkboxes as $k => $v) {
  echo '<label for="seminar_'.$k.'">'.$v.'</label><input type="checkbox" name="seminar['.$k.']" id="seminar_'.$k.'" value="'.htmlentities($v).'" '.(isset($_POST['seminar'][$k]) ? 'checked="checked" ' : '').'/>';
}

answered Jan 17, 2011 at 20:45

Michael Irigoyen

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3 Comments

OldWest Over a year ago

Michael, your comment was very helpful : ). This is what I did, and it's all working now: <?php if(isset($_POST['seminar']["$a"])) { $checked = "checked=\"checked\""; } else { $checked = ""; } ?> <input name="seminar[<?php echo $a; ?>]" type="checkbox" id="seminar_<?php echo $a; ?>" value="" <?php echo $checked; ?>>. , but when I am trying to insert into my table using (existing code) this no longer works: if($seminar) { foreach ($seminar as $s ) $interest .= "$s "; }. any idea how I can process this new array structure based on a foreach()?

Michael Irigoyen Over a year ago

Glad I can help. One thing, you don't need double quotes around $a in isset($_POST['seminar']["$a"]). Just do isset($_POST['seminar'][$a]).

OldWest Over a year ago

Cool. Thanks for the added tip :-) .. I am going to create a new thread to my other question as it's somewhat a different topic.

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