form validation

Validation is a simple process of testing to ensure that the user has filled the required information with proper formatting through the web form.

To understand a validation properly, go to any popular website that contains a registration form, and you will observe that they provide instant feedback when you don’t enter your data in the format they’re expecting. You will be getting errors such as:

  • “This field is required” (You can’t leave this field blank.)
  • “Please enter your phone number in the format xxx-xxxx” (The form enforces three numbers followed by a dash, followed by four numbers.)
  • “Please enter a valid email address” (Used if your entry is not in the format of “somebody@example.com.”)
  • “Your password needs to be between 8 and 30 characters long and contain one uppercase letter, one symbol, and a number.”

Yes, this is called Validation. When you enter some data into the field, the web application checks it to see if the provided data is in the correct format to avoid any confusion. If it is in the correct format, the web application allows the data to be submitted to the server and (usually) saved in a database; if the information is in the incorrect format, it gives you an error message explaining what needs to be amended.

Different Types Of Validation

There are two types of form validation one can encounter on the web; Client-side Validation and Server-side Validations.

Client-side Validation :

Client-side validation occurs in the browser before the data has been submitted to the server. It is generally used to provide quick response/feedback to the user. Feedback such as, highlighting the input box with red that failed, tooltips explaining that the email address doesn’t look valid, explaining that the “Amount to pay off your credit card” should be higher than 0, etc.

Client-side validation is further subdivided into the following categories:
1) JavaScript validation is coded using JavaScript. This validation is completely customizable.
2) Built-in form validation uses HTML5 form validation features. This validation generally does not require JavaScript. Built-in form validation performs better than JavaScript. The native validation is not as customizable as JavaScript.

Server-side Validation :

Server-side validation occurs on the server after the data has been submitted. Server-side code is used to validate the data before the data is saved in the database or otherwise used by the application. If the data fails validation, a response is sent back to the client with corrections that the user needs to make. It can be done using programming languages like C#.NET, VB.NET, etc.
Server-side validation is more secure than the client-side as the user cannot see the code even he does a view-source.

Why We Need A Validation?

You need validation as a security measure. It is required to prevent web form abuse by malicious users. Improper validation of form data is one of the main causes of security vulnerabilities. It exposes your website to attacks such as header injections, cross-site scripting, and SQL injections.

  • Header injection attacks can be used to send email spam from your web server
  • Cross-site scripting may allow an attacker to post any data to your site.
  • SQL injection may corrupt your database backend.

Form validation is important for way more reasons than these, but these are the three that we have seen destroy projects.

Conclusion :
Both the validation methods have their own significance. We would like to recommend that you should use both the validation methods Client-side validation to provide a better user experience and server-side to be sure that the input you get from the client (browser) is actually validated and not just supposed to be validated by the client.

However, if you’re still getting confused with this topic, please feel free to get in touch with our Ace Web Developers at AMH Web Studio.