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How to perform user input validation in forms using Javascript.

Javascript has been mainly used for website making all over the world due to its versatile, dynamic, and interactive performance. It gives the best forum for the users to work on indeed. However the JS form validation goes one step further to avoid errors in the forms before submission.

Validation becomes a must in validating the user inputs and replies. The Web developers prefer javascript for their form validation creation and the secret happens to be the ease of usage. Unlike others, js uses the validation on the client side hence it is faster, smoother, and cost/time efficient.

Image credits- Coding Ninjas

What is Form validation using JS?

User input validation is just like checking all the answers before giving out the exam papers indeed. Javascript is the witty scripting language that has been used in almost all the websites in the network. Not only can the Js be so versatile in working and creating interactive web pages but also it can do form validation.

In this one, the js validates or verifies that the answers/inputs that the user provides match the correct ones or so. If not then the form just won't submit rather it shows the pop-up message saying please input the required fields with a proper response. In a nutshell, the major goal has been to avoid or remove all the errors in the form before submitting it.

How to use JavaScript for user input validation in forms before submission.

Javascript form validation or we can simply do the HTML form checking via javascript. In both ways, the form validation entity checks if the typed text or number must meet the requirement. The feed-ins are already verified so that it ensures time-saving and eliminates errors.

For instance; 

function validateFormdesc() {

  let a = document.forms["myFormdesc"]["fname"].value;

  if (a == "") {

alert("Fill out the name");

    return false;



In the above example, we saw the function to prevent the form from being submitted when the ‘key in’ becomes nil or without needed information. It states the popup quote as ‘fill out the name’ when no name has been replied to.

Moreover, it doesn't stop there but also can be used for number validation such as phone numbers, dob, and so on. When the user types in the wrong digits or lesser digits or no digits then the popup says 'Your no. not valid’.

HTML form auto-validation

Apart from all the validation methods above, the automatic checking using HTML and HTML form has been no less. This case used to be automatically executed via the browser(a program that provides the system to see and respond with the internet info). The browser confirmation on the other hand becomes quicker.

It has been verified immediately on the browser itself. If the form document has no inputs then the required attribute won't allow it to submit. It also says that ‘fill the field to proceed’ or so. However, this kind of validation doesn't seem to function on Internet Explorer 9 or versions before that.

The form/text feed makes sure of the neat and correct inputs hence it stands to be a useful attribute. The Confirmation of the information put in has been done using different ways. Mostly it happens to be there to capture the correct data.

  1. The answer must be present in all the mandatory fields.

  2. The answer should be valid.

  3. The numeric and text boxes must not collide. The user should not enter the text into the number box and vice versa.

  4. The form validation has been performed either on the server side or the client side. On the client side, the browser validates the data before it goes to the web server. Hence it seems to be faster instead the input gets validated only after it goes to the server in the server-side authentication.

We surely require HTML and JavaScript to build the website, and forms and also for validating the forms using JS. Do read our basic to advanced writings on web development and web design to make use of it and develop huge in the digital market. We also do all types of courses, internships, and projects.

It does match perfectly with your IT work needs and career counsel too. Our team has had the best hands-on web development courses and projects in the light of seven years. Our specialist coaches have come across the customised platform for you to get hands-on web development experience to enhance your employment everywhere.

You need your work life to get sky-rocketed, we provide all the tools and techniques just for that. We would be sure to achieve that in the IT project training with our IT team of masters. We also have the design forum to expand full-on mode and whatnot. Reach out to our team via email, chat, or call for more info.


3 Benefits of Form Validation Using JS

  • Faster show-it validates the user key in with the client side for a faster checking speed.

  • User-friendly- provide an abundant presentation.

  • Popups with no need to refresh- it gives the needed output without page reloading using its dynamic forms.

What are the techniques to validate user input in JS? 

HTML has newly developed HTML 5 form attributes for validation techniques. Client-side validation also has a major impact on managing to keep up with the speed of today's generation. 

What is user input validation?

The user response should be verified for authentication. The form provider has a set of parameters to be met during the form submission. If it goes otherwise the js comes to rescue by righting the wrong with necessary instructions as popups. 

Click on to view the visual depiction-


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