What is validation in php

Required field will check whether the field is filled or not in the proper way. Most of cases we will use the * symbol for required field.

What is Validation ?

Validation means check the input submitted by the user. There are two types of validation are available in PHP. They are as follows −

• Client-Side Validation − Validation is performed on the client machine web browsers.

• Server Side Validation − After submitted by data, The data has sent to a server and perform validation checks in server machine.

Some of Validation rules for field

Valid URL

Below code shows validation of URL

$website = input($_POST["site"]);

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

Above syntax will verify whether a given URL is valid or not. It should allow some keywords as https, ftp, www, a-z, 0-9,..etc..

Valid Email

Below code shows validation of Email address

$email = input($_POST["email"]);

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
   $emailErr = "Invalid format and please re-enter valid email"; 
}

Above syntax will verify whether given Email address is well-formed or not.if it is not, it will show an error message.

Example

Example below shows the form with required field validation

   
   
      
   
   
   
      
     
      
Absolute classes registration
     
      
* required field.
     
      
">
         

            

               
Name:
               

                  * 
               
            
           
            

               
E-mail: 
               

                  * 
               
            
           
            

               
Time:
               
 
                  
               
            
            
            

               
Classes:
               
 
            
            
            

               
Gender:
               

                  Female
                  Male
                  * 
               
            
				
            

                
            
				
         
			
      
      
      Your given values are as:";
         echo $name;
         echo "
";
         
         echo $email;
         echo "
";
         
         echo $website;
         echo "
";
         
         echo $comment;
         echo "
";
         
         echo $gender;
      ?>
   
   

It will produce the following result −

Can validation be done in PHP?

What is the use of validation?

What is the importance of validation in PHP?

What are the two types of validation?