[Resolved] calling a PHP function with HTML

wheeler08

I have a PHP function that I need to call when the SUBMIT button is clicked on a form.

The PHP function is opening the database and comparing values enetered on the form to those in the database.

I am mixing HTML, PHP and Javascript (other functions on the page).

How do I call the PHP function when the submit button is clicked?
How should I code my function at the top?

Here is the function as I have it now:

function checkname()
	{
	//connect to db
	Require_once('myConn.php');

// check to see if the name has already been used
$SQL = "SELECT * FROM tblproperties WHERE name='$name'";
$result = mysql_query($SQL);
$numrows = mysql_num_rows($result);

if ($numrows >=1) {
echo '<SCRIPT LANGUAGE=JAVASCRIPT TYPE="TEXT/JAVASCRIPT">';
echo 'alert("A property with this name already exists, please change the name.")';
echo '</SCRIPT>';
exit;
}
}

If there is an easier way to do this with just Javascript, I'm up for it! The whole point to this thing is that a popup message will alert the user when a record is being written to the database twice.

pablogosse

Hi there.

Since PHP is a server-side language and javascript is client-side, what you want to do cannot be done simply with Javascript, as you need to take the data from the client and verify in the database (on the server) that it doesn't already exist.

What you'll need to do is have a php file that accepts the values submitted from the form and which then calls the function you've defined below.

If the record already exists in the database, then you need to catch this error and redirect the user back to the form and display an error message indicating this.

I'm on my way out of the office now but I'll check back later tonight and if nobody's provided a code sample I'll get one from my library which you can use.

Cheers,
Pablo

wheeler08

Thanks a lot Pablo. I appreciate that. I'll look forward to your response 🙂

kellog

Please excuse any errors, I'm writing this off the top of my head

<html>
<head>
	<title>Untitled</title>
</head>

<body>

<?
function Form($Error = NULL, $UserName = NULL)
{
	?>
	<form action="ThisPage.php" method="post">
		<?=$Error?><br>
		<br>
		UserName: <input type="text" name="UserName" value="<?=$UserName?>"><br>
		Password: <input type="Password" name="Password"><br>
		<input type="submit" name="Submit" value="Login">
	</form>

<?
}
?>

<?
function ParseForm($UserName, $Password)
{
	<open database, check for duplicate name>
	if ($DuplicateName)
	{
	     Form("That name already exists, please choose another.", $UserName);
	}
	else
	{
		<add data to the database>
	}
}

if ($_POST['Submit'] == "Login")
{
	ParseForm($_POST['UserName']), $_POST['Password'];
}
else
{
	Form();
}
?>

</body>
</html>

superwormy

PHP is SERVER SIDE, it can't do anything like open a popup window, you need a CLIENT SIDE language to do that ( Javascript )

You cannot call a PHP function when the submit button is clicked. PHP does NOTHING until after the browser submits the form and the HTTP request to the server.

pablogosse

Hi there. Sorry for the delay in responding. Below is the methodology you will have to follow to do what you are looking for:

1) HTML FORM

Build your standard html page with the form in question. But somewhere in the area of the form, you will want to add the following check:

<?php
if (!isset($_GET['db_err']) || $_GET['db_err'] != 1) {
  echo '<strong style="color:#ff0000">output error message</strong>';
}
?>

This will be used after you've processed the form and checked if there are any errors.

In the input field for the name

<input type="text" name="name" value="<?php if (isset($_GET['name']) echo $_GET['name']; ?>" />

2) PHP PAGE TO PROCESS FORM DATA

You will need to write the code that will process the form data, and perform the check you've coded in the ParseForm function below. Then based on the results of $numrows from your ParseForm function

<?php
if ($numrows >=1) {
  // set the db_err flag to 1 and on form.php the error message will be displayed
  header('Location:form.php?db_err=1&name='.$_GET['name']);
} else {
  // do what you will if no error reported
}

Hope this helps.

Cheers,
Pablo

pablogosse

Sorry, just noticed a small error in the code.

Where the text field is output, the code that checks for the name and outputs it needs to have another ) added to the if statement.

if (isset($_GET['name']))

Cheers,
Pablo

wheeler08

Here is my parseform page... when it loads, I get the following error:

Warning: Cannot add header information - headers already sent by (output started at C:....\form.php:8)

Also, when the original form loads, the error message is displaying everytime. Any ideas?

<?php
	$name = $HTTP_POST_VARS['propertyname'];
	//connect to db
	require_once('myConn.php');

// check to see if the name has already been used
$SQL = "SELECT * FROM tblproperties WHERE name='$name'";
$result = mysql_query($SQL);
$numrows = mysql_num_rows($result);

if ($numrows >=1) {
// set the db_err flag to 1 and on form.php the error message will be displayed
   header('Location:form.php?db_err=1&name='.$_GET['name']);
   } else {
  // do what you will if no error reported
}

stolzyboy

when using the header functions, you can't have any whitespace, <html> type tags, etc... before the function call...

optionally, you can put

ob_start();

as the first line of code to suppress the error, but keep in mind, this will keep all the overhead of your output on the server

pablogosse

The "Cannot add header information" occurs when you're trying to use the header() function after already having sent the headers to the browser.

That is, you're trying to use it after you've already output some content.

There are two ways around this:

1) Remove any outputs to the browser before the header() call.

or 2) Use an http meta-refresh to redirect the pages. This isn't the most elegant way, but sometimes it's almost unavoidable.

Regarding the error showing up every time, I'll attribute that to me still being half asleep when I wrote that....my appologies.

The code should be:

if (isset($GET['db_err'] && $GET['db_err'] == 1) { .....

That way it checks that a) the var is set, and b) that it equals 1 before outputting the message.

Cheers,
Pablo

wheeler08

I have changed the header line of your script and it works (I have used javascript instead of php)

echo '<SCRIPT LANGUAGE=JAVASCRIPT TYPE=TEXT/JAVASCRIPT>';
   echo'window.location=("admin_newproperty.php?db_err=1&propertyname="'.$_GET['propertyname'].')';
   echo'</SCRIPT>';

Is this bad practice?

stolzyboy

it can be if peeps have javascript turned off

pablogosse

Yup, I'd use the http meta-refresh to avoid any issues if people have javascript turned off (though I've never run into anyone who turns off javascript).

BSTS though.

wheeler08

value="<?php if (isset($_GET['name']) echo $_GET['name']; ?>">

isn't working....

here's the error

Parse error: parse error, unexpected T_ECHO in ....

what am I missing here?

pablogosse

Does the file in question have a .html or .php extension? If the PHP code is being literally output, then chances are it's got a .html extension.

Cheers,
Pablo

wheeler08

Sorry --

It was that extra bracket... I thought I had changed it.

Ok - so this works! Thanks for your help gentlemen. Consider this thread resolved 🙂

stolzyboy

you can mark it resolved then, right 🙂

wheeler08

Is it not resolved? I clicked the link at the bottom of the page........

pablogosse

Stolzyboy: How does one mark a post as resolved? Is there way for a user to remove a post if they don't want it to be in the BB anymore?

Also, is there an option whereby users could edit existing posts? I've seen a few other forums which have that option. Very nice.

Cheers,
Pablo

stolzyboy

i did it for ya, sometimes on certain occasions the link doesn't work correctly depending on which way you came to the thread