Recursive programming in php

masha · #1 (**permalink**) Sep 29th, 2007, 21:44

I'm very very very new to PHP.
I have a PHP doc.
What I cannot do:
There is a form inside the php file.
When user enteres values into the form I want php to analyze the values and if there is a problem to right next to the form field what the problem is. But instead of it before the values are entered into the form the message comes up. How to make the message to analyze the data after the form is processed.
There are many more problems with the document but this is the most disturbing one.
Thank you guys.
This is the code:

PHP: Select all


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
        <title>Untitled Document</title>
 
    </head>
    <body>

    <h1>My Bills</h1>
<form method="POST">
    <table>
       <tr>
          <td>Item</td>
          <td>Amount</td>
</tr>
  <?php
     
    
        for($i=1;$i<5;$i++)
           {
            $counter=$i;
            $item_name='items'.$counter;
            $item_value = $_POST[$item_name];
            
            $amount_number='amount'.$counter;
            $amount_value = $_POST[$amount_number];

           echo "<tr><td><input type=text name =$item_name value=$item_value></td>";
              
                   
            echo" <td><input type=text name =$amount_number value= $amount_value></td>";

              
           

</table>
   <input type="submit" name ="submit_button" value ="Submit" />
</form>
$amount_number=$_POST[$amount_number];
           if(empty($amount_number)){ 
           echo"<td>Please enter an amount</td>";/* I don't want this sentence to be here, but i don't know how to leave the space in between the brackets empty.*/
             }
             
           if(!is_numeric($amount_number)){

            
 
           echo"<td> Amonut $amount_number is not a number</td>";/*How to make this statment to appear only when the info is already entered?*/
           $counter++;
           echo"Errors: $counter";}
   
          if($amount_number<99 && $amount_number>100001)/* This statemnt doesn't work at all!!!! */
{
          
                    echo"<td> Amount $amount_number should be between 100 and 100000</td></tr>";
                    $counter++;
                    echo"Errors: $counter";
                  }
           
          
 
 
 
 
          }

      ?>
 
    </body>
</html>

split-visionz · #2 (**permalink**) Sep 30th, 2007, 03:35

My favorite way to validate forms is to actually add a javascript function to validate the form attributes when the submit button is clicked and use javascript to add error messages to the innerHtml of the <td> tags where you want. You would need to give each <td> a unique Id inorder to do it.

If you must do it in PHP use the ISSET() function to check whether a POST variable is set before you print out the error messages.

simonb · #3 (**permalink**) Sep 30th, 2007, 19:07

Can you put the code in the php bbc

Rakuli · #4 (**permalink**) Oct 1st, 2007, 11:51

Your PHP is a little wacky (sorry

)

There is no real procedure as the loop hasn't finished before you start checking things.

The script below is yours but I have rewritten it to do as you ask but also work -- it will check each condition and only display error messages if needed after the form is submitted.

PHP: Select all


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />

<title>Untitled Document</title>



</head>

<body>



<h1>My Bills</h1>

<form method="POST">

<table>

<tr>

<td>Item</td>

<td>Amount</td>

</tr>

<?php





for($i=1;$i<5;$i++)

{



$item_name        = 'items'.$counter;

$amount_number    ='amount'.$counter;







// These will hold the error messages if/when they occur

$item_error = false;

$amt_error = false;



// This will check to make sure the form has actually been submitted

// Allowing you to display error messages should they be required

if (!empty($_POST['submit_button']))

{

    // Trim the white space that might trick PHP into thinking there is something when there isn't

    $item_value     = trim($_POST[$item_name]);

    $amount_value   = trim($_POST[$amount_number]);

    

    // Now check that fields have been set

        if (empty($item_value))

            $item_error = 'You much enter an item name!';

        

        if (empty($amount_value))

            $amt_error = 'You must enter an amount';

            

        // This will check to make sure that the amount is a number

        else if (!is_numeric($amount_value))

            $amt_error = 'Your amount must be a number';

        

        // This will check that it is not less than 99 **OR** greater than 100000

        // In your script you were checking to see if it was less than 99 **AND** greater than 100000 (obviously a tough feat)

        else if ($amount_value < 99 || $amount_value >  100000)

            $amt_error = 'Your amount can\'t be less than 99 or greater than 100000';

            



}







// We will use a ternary to see if there is an error with each field



echo '<tr><td><input type="text" name="', $item_name, '" value="',$item_value, '" />',/* Is there an error? If yes, display it next to the input */ ($item_error ? '<br />' . $item_error : ''), '</td>';





echo ' <td><input type="text" name="', $amount_number, '" value="', $amount_value, '">', ($amt_error ? '<br />' . $amt_error : ''), '</td>';



} // Close the for loop and finish the HTML



?>

</table>

<input type="submit" name="submit_button" value ="Submit" />

</form>



</body>

</html>

Quote:

Originally Posted by split-visionz

My favorite way to validate forms is to actually add a javascript function to validate the form attributes when the submit button is clicked and use javascript to add error messages to the innerHtml of the <td> tags where you want. You would need to give each <td> a unique Id inorder to do it.

If you must do it in PHP use the ISSET() function to check whether a POST variable is set before you print out the error messages.

A server side checking option is really not debatable. Javascript is great to save a round-trip to the server but can be switched off. You can't switch PHP off so it is by far more secure than javascript.

Hope that helps, cheers.

c010depunkk · #5 (**permalink**) Oct 1st, 2007, 12:37

Quote:

Originally Posted by Rakuli

A server side checking option is really not debatable. Javascript is great to save a round-trip to the server but can be switched off. You can't switch PHP off so it is by far more secure than javascript.

Or use both. The client-side check increases Usability and the server-side increases safety....

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Recursive programming in php