如何查看 PHP 中选中了哪些复选框？

Question

I'm displaying some columns from a database and at the end of each row I put a check box.

while($row = $result->fetch_assoc()){
    echo "<tr><td>" . $row['Computer Name'] . '</td><td>' . $row['Computer IP'];
    echo ($checkbox)?('<td><input type="checkbox" name="selectSystem"/></td>'):'' . "</td></tr>";
}

(Ignore my $checkbox variable, that's just a function parameter allowing me to toggle the check boxes on/off when I display these rows.)

The code above works fine, but I can't figure out how to output the value (check or unchecked) of these check boxes. It is my understanding that all the check boxes have the same name ( selectSystem ) and that they should all be in a selectSystem array.

Maybe I'm going about this in the wrong way...I just want the user to be able to select the rows they want in order to reserve a computer system. Is there an easier way to do this or should I just continue on with my stupid check boxes that get rallied up after a submit button is clicked?

Answer 1

As Dharman suggested, use an iterator with your while loop to create your name attribute so each name is different. Then once your user hits the submit button, the global $_POST variable will hold the values of the checkboxes they have selected.

Consider the following code example..

// define a variable to hold your output in...
$output = null;

// as I do not have your database result, I will use an example array of values
// to get a length to use in a while loop to show the iteration using a declared number
// that is iterated within your while loop until the length of the array is reached
$array = [1,2,3,4,5,6,7,8]; //--> Here we have 8 values in the array
// define a number to use as iterator or a counter
$i = 1;
// while loop iterates through array while our counter is less than the number within  our array
while($i < count($array)){
    // concatenate our output variable to include the next input 
    // Each time we iterate through to the next value in our array
    // we concatenate the next numbers iterated value by 1 to our name attribute
    // now your name attribute is uniquely named 

 
    $output .= '<input type="checkbox" name="selectSystem'.$i.'"/>';
    $i++;
}

OUTPUT:

<input type="checkbox" name="selectSystem1"/>
<input type="checkbox" name="selectSystem2"/>
<input type="checkbox" name="selectSystem3"/>
<input type="checkbox" name="selectSystem4"/>
<input type="checkbox" name="selectSystem5"/>
<input type="checkbox" name="selectSystem6"/>
<input type="checkbox" name="selectSystem7"/>
<input type="checkbox" name="selectSystem8"/>

Now once you want to access these values once the user presses the submit button onthe form, the array lives in your $_POST array. Just check a strict conditional for 'on' to access the values for the checkboxes that are checked...

// we define a variable to hold our results and assign a null value to it so when not set it shows nothing...
$stmt = null;
// if our $_POST isset...
if(isset($_POST)){
    // loop through results and use a strict conditional on the $value each loop through
    foreach($_POST as $key => $value){
        if($value === 'on'){
            // concatenate the variable to hold the key and value foreach result
            $stmt .= $key.' -> '.$value.'<br>';
        }
    };
}

<form method="post">
    <?=$output?><!--/ Echo your $output which holds the inputs/-->
    <input type="submit" value="submit" name="submit">
</form>

<?=$stmt?><!--/ Echo your $stmt which holds the $_POST array values of your checkboxes that are 'on', if this variable is null it shows nothing in your html /-->

Answer 2

The easiest way of handling forms is through JavaScript not directly in php because you have to use expensive work around for things like form validation and security

If you not using some method of sanitizing the form input you open your self up to SQL injection attacks so it good to handle form values in JS and use a rest api for transferring the results to the PHP server

I used to do the forms like you but I realized A: its more work and B:you don't get a chance to format form responses in a way that is predictable

 //get the button event const btn = document.getElementById('btn'); //event btn.onclick = () => { // get the element and see if it is checked let cb = document.getElementById('accept'); console.log(cb.checked); /// once all your form data is prepped send to the server through an XHR request //PHP rest API should handle the receiving side };

 <form> <input type="checkbox" id="accept" checked> Accept <input type="button" id="btn" value="Submit"> </form>

Another major reason for doing things like this is that if your server is busy with a long query like handling multiple users, data base queries,or making a PDF document...

you client browser will hang and wait for the server to finish.... but by using JS with xhr requests and things like await sinc the clients browser wont freeze if the server is busy with heavy computational tasks. Doing things this way will ensure you user interface is always active and adds to the smoothness of your program

I trust this help you