Questoin related to Php Form

lhua059

hi there, i need to write a single php file which would analyse the form data(the form is within the same php file) such as ID, Car Registration number etc.. i need to validate the user data too, if it is all vaid then display the summary page about the user data, if the user data is invalid, i need to re-display the form again with the correct data staying in the field and empty those filed with invalid data, so my question is how i can display the form inside if(valid){} can i make call to the form? Any help would be appreciated!!

<html>
        $studentID=$_Post['stuID'];
        $stuGender =    $_Post['gender'];

    if(studentid not in a valid format){
      \\   display the form again with the correct gender showing in the field
       \\  and the stuID field should be empty here, 
       \\  i'm not quite sure how to do here as i m new to php
    }

    <h1>Tamaki online car park booking system</h1>
    <form action="comboform.php" method="post">
      <p>Please enter your AUID:
      <input type="text" name="stuID" value="<?php echo $_POST['stuID']?>">
      <input type="text" name="gender" value="<?php echo $_POST['gender']?>">
      <input type="submit" value="Submit">
    </form>
  <?php
  }
?>
  </body>
</html>

bpat1434

Well, there are two options:
1.) Use javascript to validate.
2.) Make the form a function 😉

Javascript could be the easiest to implement as you can just show an alert box if it doesn't validate, and if all the stuff does validate, just post the info to the next page.

Putting the form in a function is rather easy too. Just take the form and create a function which takes a parameter which is an array of errors or error codes. Here's a sample:

<?php
$errors = array();

// Set errors:
if(!is_numeric($_POST['stuID']))
    array_push($errors, 'stuID');
if(!is_string($_POST['gender']))
    array_push($errors, 'gender');

showForm($errors);

function showForm($e)
{
  echo '<form action="comboform.php" method="post">
    <p>Please enter your AUID:
    <input type="text" name="stuID" value="'.$_POST['stuID'].'"'.((in_array('stuID', $e))?'style="background-color: #f00; color: #000;"':'').'>
    <input type="text" name="gender" value="'.$_POST['gender'].'"'.((in_array('gender', $e))?'style="background-color: #f00; color: #000;"':'').'>
</form>';
}
?>

It's very basic, but it works.

scrupul0us

just a sidebar... to make coding easier, instead of doing this:

<?php echo $_POST['gender']?>

do this:

<?=$_POST['gender']?>

no need for echo and reduces the script tag size 🙂

bpat1434

Ah, but that is not supported on all servers, so be careful!!

If shorttags are off (which a lot of places have it off) then you need <?php echo.... if shorttags are on, you can use that. But if I remember correctly, it's being deprecated in PHP 6... so eventually if you never update your code and the server updates its software, you have potential for breaking the script.

As a general rule, it's best to code to the majority and most widely accepted standard. So just because <?= makes it easier, doesn't mean it will work everywhere. Using <?php echo guarantees that it will work because no matter what, you will echo whatever unless the echo function becomes deprecated (wouldn't that be a hoot).

And using the <?= method still doesn't solve his problem completely.... the function given to him would do it nicely, and give the "malformed" fields a red background so that visually they can see where they went wrong.

lhua059

Thank you guys for your replies...i'm working on it now...cheers

scrupul0us

are you serious? why would they depreciate that.... thats my favorite trick 🙂

but i kind of agree... always code <?php for maximum compatibility

thanks for the heads up

good luck lhua059

lhua059

i sort of fix the problem with displaying the form again when invalid data is entered ..Bascially what i program does is that getting the student to enter their student ID and their car registraton number, and choose from within the next five following day(counting from one day after the form being submited successfuly) eg if today is the 20th April, then there will be five check boxes with the date(21 April,22 April.....25 April) as the label the student can choose from . The student ID field must be 7 digits, and the registration field either 2 Upper case letter followed by 1 to 4 digitss or 3 UPPER CASE letter followed by 1 to 3 digits. below is a brief summy of my program.

<?php
	if(count($_POST)>0){

		$AUID=$_POST['stuID'];
		$REGO=$_POST['regNO'];


		//check the validity of the student ID
		if(!preg_match("/^(\d{7})$/",$AUID)){
					$IDNotValid=true; $field="AUID";
					$AUID = "";
		}

		//check the validity of the registration number
		if(!(preg_match("/^[A-Z]{2}[0-9]{1,4}$/",$REGO)||preg_match("/^[A-z]{3}[0-9]{1,3}$/",$REGO))){
						$RegNotValid=true; $field="Registration Number";
						$REGO="";
		}

		if($IDNotValid){

		//	display the form again,the stuID field would be empty in this case but with the correct registration number
		//in the regNO field in the form
			echo " some form data  here"
		}

		if($RegNotValid){
		// display the form again,the regNO field would be empty in this case but with the correct Student ID in the stuID field
			echo "some form data here"
		}


}
else{?>
[code=html]
		<html>
			<body>
				<p>Welcome To Tamaki Online Car Park Booking System</p>
				<form action="comboform.php" method="post" />
				<input type="text" name="stuID" value="<?php echo $_POST['stuID'] ?>">
				<input type="text"  name="regNO" value="<?php echo $_POST['regNO']?>">
				<input type="checkbox" name="dates[]" value="day1">
					.
					.
					.
				<input type="checkbox" name="dates[]" value="day5">
			</body>
		</html>

}

?>
[/code]

My question is when invalid info is provided , the form should keep displaying until the student have provided all the valid information. but how can i refer to the correct info entered previously by the student? thanks in advance

bpat1434

Use a funciton... as in my first example....