I am learning PHP through w3schools. I am little bit confused of the execution flow of the page. I will attach a code example from w3schools.
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<input type="radio" name="gender" value="other">Other
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
Can anyone explain how the execution flow goes on this form handling. Browser can't run the php script. In this example superglobal $_SERVER["PHP_SELF"] used to refer the same html page. when we try to submit the page with empty field it shows the error message in screen. This is happening due to the fact php variable got its error value after submission. I think that after triggering the submit button. This page makes a request to the same page in the server using POST method and in the server we access the same form value using superglobal $_POST["name"],["email"] etc.. and finally the server throws the new html page. Am i right? or this validation is happening entirely in the frontend.
In php the validation is happening entirely in the server ..
The frontend only validate things when JavaScript involved or you add field attributes like required , min , max.
I think w3 is good source to check small code snippets. but it's not good source to learn
Related
I am creating a php form for data validation but there are some errors that I can't find.
When I submit the form the required notification is displayed. But when I reload the page then the required notification still remains. My code is:
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
// check if e-mail address is well-formed
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&##\/%?=~_|!:,.;]*[-a-z0-
9+&##\/%=~_|]/i",$website)) {
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name" value="<?php echo $name;?>">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email" value="<?php echo $email;?>">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website" value="<?php echo $website;?>">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment;?></textarea>
<br><br>
Gender:
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?>
value="female">Female
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?>
value="male">Male
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="other") echo "checked";?>
value="other">Other
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
This is the result when I first type the address in the browser.
This is the result when I enter an empty value in all the fields and submit the form. This will remain when I reload the page and until I close the browser tab and open a new tab and enter the url again.
You got error message when you reload after form submission. Try following code into your JS file or in JS code.
<script>
if ( window.history.replaceState ) {
window.history.replaceState( null, null, window.location.href );
}
</script>
Hope this will help you!
I'm super new at coding. This is the form page code
<?php
// Start the session
session_start();
?>
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
$fnameErr = $emailErr = $addressErr = $countryErr = $stateErr = $suburbErr = "";
$fname = $email = $address = $country = $state = $suburb = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["fname"])) {
$fnameErr = "Name is required";
} else {
$fname = test_input($_POST["fname"]);
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
}
if (empty($_POST["address"])) {
$addressErr = "Address is required";
} else {
$address = test_input($_POST["address"]);
}
if (empty($_POST["country"])) {
$countryErr = "City is required";
} else {
$country = test_input($_POST["country"]);
}
if (empty($_POST["state"])) {
$stateErr = "State is required";
} else {
$state = test_input($_POST["state"]);
}
if (empty($_POST["suburb"])) {
$suburbErr = "State is required";
} else {
$suburb = test_input($_POST["suburb"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2 align="cemter">Check out</h2>
<p><span class="error">* required field</span></p>
Full Name: <input type="name" name="fname">
<span class="error">* <?php echo $fnameErr;?></span>
<br><br>
E-mail: <input type="email" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Address: <input type="text" name="address">
<span class="error">*<?php echo $addressErr;?></span>
<br><br>
Country: <input type="text" name="country">
<span class="error">*<?php echo $countryErr;?></span>
<br><br>
State: <input type="text" name="state">
<span class="error">*<?php echo $stateErr;?></span>
<br><br>
Suburb: <input type="text" name="suburb">
<span class="error">*<?php echo $suburbErr;?></span>
<br><br>
<form method="post" action="../mailer/index.php">
<input type="submit" name="submit" value="Purchase">
</form>
</body>
</html>
But after I fill up all the information and click submit, the page said cannot connect to SMTP sever host. The strange thing is, I can send email while run the phpmailer index.php alone. The form page php file and the mailer php file is in a different folder but same parent folder, is this the problem?
If one page works and another doesn't, and these are in different folders, then yes, that could be the problem. However, the solution is probably not to just move one of the files (which would probably give you other path related issues), but instead make sure that they both can reach the neccessary configuration (SMTP server host in this case).
I'm recieving an issue in the following php code. I am recieiving an unknown variable error in line 146, (echo $newrecord) variable. I'm not sure what is wrong with this variable, I have defined it in the IF statement, and am simply echoing if it is successful. I originally had that segment of code (after ) at the top of the script, but it was causing issues with the mandatory field error messages displaying properly. Any help is appreciated!
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = $subErr = "";
$name = $email = $gender = $comment = $website = $sub = $newrecord = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["Name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["Name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["Email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["Email"]);
// check if e-mail address is well-formed
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
if (empty($_POST["Website"])) {
$website = "";
} else {
$website = test_input($_POST["Website"]);
// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&##\/%?=~_|!:,.;]*[-a-z0-9+&##\/%=~_|]/i",$website)) {
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["Comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["Comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
if (empty($_POST["Subscription"])) {
$subErr = "Subscription is required"; }
else {
$sub = test_input($_POST["Subscription"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>Southern Tier Daily News</h2>
<form method="post" action="Newspaper3.php">
<input type="hidden" name="submitted" value="true"/>
<img src="https://bloximages.newyork1.vip.townnews.com/dnews.com/content/tncms/custom/image/5eec4204-483e-11e6-93c8-97ef236dc6c5.jpg?_dc=1468334339" alt="HTML5 Icon" style="width:128px;height:128px;">
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<fieldset>
<legend>Newspaper Subscription Request</legend>
Name: <input type="text" name="Name" value="<?php echo $name;?>">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="Email" value="<?php echo $email;?>">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="Website" value="<?php echo $website;?>">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="Comment" rows="5" cols="40"><?php echo $comment;?></textarea>
<br><br>
Gender:
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?> value="female">Female
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?> value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
Subscription:
<select name="Subscription">
<option value=""></option>
<option value="Daily">Daily</option>
<option value="Evening">Evening</option>
<option value="Weekly">Weekly</option>
<option value="Monthly">Monthly</option>
</select>
<span class="error">* <?php echo $subErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
<br><br>
Visit Admin Page
</fieldset>
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
echo "<br>";
echo $sub;
?>
<?php
if (isset($_POST['submitted'])) {
include('connect-mysql.php');
$fname = $_POST['Name'];
$femail = $_POST['Email'];
$fcomment = $_POST['Comment'];
$fsubsciption = $_POST['Subscription'];
$sqlinsert = "INSERT INTO newspaper (Name, Email, Comment, Subscription) VALUES ('$fname',
'$femail', '$fcomment', '$fsubsciption')";
if (!mysqli_query($dbcon, $sqlinsert)) {
die('error inserting new record');
} // end of nested if statement
$newrecord = "1 record added to the database";
} // end of main if statement
?>
<?php
echo $newrecord
?>
</body>
</html>
newrecord is defined and initialized inside the if statement, therefore if your code opts to the else, it will skip the if and your newrecord variable won't exist.
$newrecord is defined within an if statement, when the if is not executed the variable is not available. You can define it by default adding $newrecord = ''; before you start the if for the submit.
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I'm doing an assignment in which I am required to use separate html and php files but am having trouble understanding how to validate my forms input as all examples I've found have both html and php in one file.
I've been following the example on w3schools:http://www.w3schools.com/php/php_form_validation.asp
My w3_example.html:
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="w3_example.php">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
</body>
</html>
My w3_example.php:
<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
}
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
I now get an "Call to undefined function test_input()" error on this line $name = test_input($_POST["name"]); in w3_example.php
Just a tip! Because you studying as I can imagine, always care about from where you study. w3schools doesn't have a good quality
code. Use http://php.net/manual/en/tutorial.forms.php from example
which is the official PHP documentation. Their sample codes, comments
etc. are by far better than w3schools.
I checked again your sample code:
Create 2 files:
index.html / index.php (in this example it doesn't care if it is .html or .php format.
handler.php
You 1st file: index.html / index.php
<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<h2>PHP Form Validation Example</h2>
<form method="post" action="handler.php">
Name: <input type="text" name="name">
<br><br>
E-mail: <input type="text" name="email">
<br><br>
Website: <input type="text" name="website">
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
</body>
</html>
Your 2nd file: handler.php
<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
This option will show your inputs in the form in a different page-URL.
That will work!
By the way, I really don't like that poor sample code.
Please, use:
<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";
if (isset($_POST["submit"])){
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
instead of
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
}
I'm using this code from W3 (http://www.w3schools.com/php/php_form_complete.asp) to make server side validation for given example form.
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
// check if e-mail address syntax is valid
if (!preg_match("/([\w\-]+\#[\w\-]+\.[\w\-]+)/",$email)) {
$emailErr = "Invalid email format";
}
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&##\/%?=~_|!:,.;]*[-a-z0-9+&##\/%=~_|]/i",$website)) {
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name" value="<?php echo $name;?>">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email" value="<?php echo $email;?>">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website" value="<?php echo $website;?>">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment;?></textarea>
<br><br>
Gender:
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?> value="female">Female
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?> value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
Although server side validation works fine,I can't put mail() function to work ONLY WHEN both $name (treated as subject) and $comment (treated as message) fields are filled.
I've tried many combinations but email is always submitted even when fields are empty.
So my question is: how to make this validated form send email only when $name and $comment fields are filled and validated?
As you are creating $nameErr when the name is invalid and $comment is an empty string when the comment is valid you can use the following conditional:
if (!$nameErr && $comment) {
}
Empty strings are considered FALSE:
http://php.net/manual/en/language.types.boolean.php
You can always use flags.
<?php
....
// let's say there are some flags for validation
if($flag1 && $flag2 && .. $flagN){
// perform email sending here
}
?>
Or you can use the default error message variables; check if they are empty
<?php
if(!empty($nameErr) && !empty($comment)){
// perform email sending
}
?>
Do the validation after you validated $name and $comment:
if($nameErr == "" && $emailErr == "") { // If they are empty, no errors where found
// Do your email validation here
}