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1) PHP Form and Required Fields
2) PHP - Display The Error Messages
3) PHP - Validate Name
4) PHP - Validate E-mail
5) PHP - Validate URL
6) PHP - Validate Name, E-mail, and URL
1) PHP Form and Required Fields
1.1) Some fields such as "Name", "E-mail", and "Gender" fields are essential and these fields cannot be empty. They must be filled out in the HTML form.
Field
|
Validation Rules
|
Name
|
Required. + Must only contain letters and whitespace
|
E-mail
|
Required. + Must contain a valid email address (with @ and .)
|
Website
|
Optional. If present, it must contain a valid URL
|
Comment
|
Optional. Multi-line input field (textarea)
|
Gender
|
Required. Must select one
|
1.2) In the following code we have added some new variables: $nameErr, $emailErr, $genderErr, and $websiteErr.
1.3) These error variables will hold error messages for the required fields.
1.4) We have also added an if else statement for each $_POST variable.
1.5) This checks if the $_POST variable is empty (with the PHP empty() function).
1.6) If it is empty, an error message is stored in the different error variables, and if it is not empty, it sends the user input data through the test_input() function:
<?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"]);}
}
?>
|
2) PHP - Display The Error Messages
2.1) Then in the HTML form, we add a little script after each required field, which generates the correct error message if needed (that is if the user tries to submit the form without filling out the required fields):
<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>
<label>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>
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3) PHP - Validate Name
The code below shows a simple way to check if the name field only contains letters and whitespace. If the value of the name field is not valid, then store an error message:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
}
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
}
The preg_match() function searches a string for pattern, returning true if the pattern exists, and false otherwise.
|
4) PHP - Validate E-mail
The code below shows a simple way to check if an e-mail address syntax is valid. If the e-mail address syntax is not valid, then store an error message:
$email = test_input($_POST["email"]);
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
5) PHP - Validate URL
The code below shows a way to check if a URL address syntax is valid (this regular expression also allows dashes in the URL). If the URL address syntax is not valid, then store an error message:
$website = test_input($_POST["website"]);
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
6) PHP - Validate Name, E-mail, and URL
Now, the script looks like this:
<?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"]);}
}
?>
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ReplyDeleteWonderful blog & good post.Its really helpful for me, awaiting for more new post. Keep Blogging!
PHP Developers in India