PHP Form - Verification Email and URL

When it comes to verification, we need to know the regular expression:

Regular expression

Regular expression is a method of describing a text rule. It is not an exact match, but a fuzzy match through some specific symbols

In PHP, we use the preg_match function to Perform regular expression matching. One parameter is our regular expression rule, and the second parameter is the text to be checked

preg_match (string $regular, string $character String[, array &$result] )

Function: Match $string variable based on $regular variable. If it exists, return the number of matches and put the matched results into the $result variable. If no result is found, 0 is returned.

^indicates the beginning;$indicates the end

Let’s take a look at the code:

The above code matches numbers starting with date. The matching results are as follows:

Matching successful

preg_matchedeThe third parameter is matched Content, usually we will pass an empty array in, because it is a call by address. After the matching is completed, the specific matching content will be obtained in the array

Example

Program running result:

Array ( [0] => date )

In regular expressions, letters are represented by \w and numbers are represented by \d (\D represents non-digits)

•+means one or more

•*means 0 or more

•?means there or not

•{n}represents the specific number

•{m, n}represents more than m and less than n

Just like the following ：

Program running result:

Array ( [0] => an )

Using or conditions can be used to match strings. If it is just a single letter or character, you can use a range representation

Use [] Indicates the value range of a character

'/[a0\.]/' can match any string containing a or 0 or .

In addition, regular expressions can also be used - To represent a set of ranges

• [a-z] represents any one of the 26 lowercase letters

• [A-Z] represents an uppercase letter

• [0-9 ] represents a decimal number

Now that we know so much, let’s look at using regular expressions to match the content of the form.

PHP - Validation Name

The following code will detect whether the name field contains letters and spaces in a simple way. If the name field value is illegal, an error message will be output:

$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z]*$/",$name)) {
$nameErr = "Only letters and spaces allowed";
}

##PHP - Verification Email

Rules: The email name can be any character consisting of letters, numbers, underscores and dots; the email must contain the @ symbol, and the following text is processed according to domain name rules

The following code will check whether the e-mail address is legal in a simple way. If the e-mail address is illegal, an error message will be output:

$email = test_input($_POST["email"]);
if (!preg_match("/^ [a-zA-Z0-9_-]+@[a-zA-Z0-9_-]+(\.[a-zA-Z0-9_-]+)+$/",$email)) {
$emailErr = "Invalid email format!";
}

PHP - Verification URL

The following code will check whether the URL address is legal (the following regular expression operation URL contains dashes: "-"). If the URL address is illegal, an error message will be output:

$website = test_input($_POST["website"]);
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0- 9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%
=~_|]/i",$website)) {
$websiteErr = "Invalid URL";
}

We will now combine the knowledge we learned above to verify the data in our form.

    PHP中文网 
    PHP 验证实例
 * 必需的字段
 "> 姓名： *  

 邮箱： *  

 网址：  

 评论： 

 性别： 女性 男性 *  

  
 您的输入："; echo $name; echo "
"; echo $email; echo "
"; echo $website; echo "
"; echo $comment; echo "
"; echo $gender; ?>