How to Work With Forms In JavaScript?: Step-By-Step Process with REAL-TIME Examples

• In this article you will learn:
• 1.Introduction.
• 2.What are forms in a JavaScript?
• 3.How to Create a form using a JavaScript?
• 4.JavaScript.
• 5.JavaScript Form Validation.
• 6.Data Validation.
• 7.HTML Constraint Validation.
• 8.Constraint Validation HTML Input Attributes.
• 9.Conclusion.

Introduction:

JavaScript serves the wide range of functionalities, for example, can create a web and mobile applications using a JavaScript, JavaScript assists us in creating special effects, etc.Another useful feature of a JavaScript is that it helps us to enhance HTML forms.Can create a forms using the tag however, JavaScript can be used for the form processing, form validation, etc.JavaScript allows us process forms without calling/invoking the server.JavaScript offers a multiple properties and methods that are used to work with a forms. For example, can use the getElementById() method to read different HTML elements, using innerHTML property can set the form’s content and so on.

What are the forms in JavaScript?

• A form is the container/holder that can hold several elements.
• In a JavaScript the concept of forms is used to collect the user’s input using different elements like input fields, buttons, labels, fieldsets, text fields, and so on.
• JavaScript can be used to interact with forms to validate the forms to process forms etc.

How to Create form using a JavaScript?

Let’s consider a below-given example to understand how to create form using a JavaScript:

HTML:

Afterward created a form using a <"form"> tag and within form tag and created two input fields and a button.

JavaScript:

HTML form validation can done by JavaScript:

• In a JavaScript file i.e. form.js, can utilized the method to read the HTML elements.
• Next, utilized innerHTML property to set a name and element.
• On successful execution of program.

JavaScript Form Validation:

• HTML form validation can be a done by the JavaScript.
• If a form field (fname) is empty, a function alerts message, and returns a false, to prevent form from being submitted.
• An Automatic HTML Form Validation.
• HTML form validation can be performed an automatically by a browser.
• If form field (fname) is empty, the required attribute prevents this form from being be submitted.
• A JavaScript Can Validate a Numeric Input.
• A JavaScript is often used to validate a numeric input.

Data Validation:

Data validation is a process of ensuring that user input is be clean, correct, and useful.Typical validation tasks are be :

• Has user filled in all the required fields?
• Has user entered valid date?
• Has user entered text in numeric field?
• Most often a purpose of data validation is to ensure that correct user input.
• Validation can be explained by many various methods and deployed in many various ways.

Server side validation: is performed by a web server after an input has been sent to a server.

Client side validation: is performed by a web browser before an input is sent to the web server.

HTML Constraint Validation:

HTML5 introduced new HTML validation concept are called a constraint validation.HTML constraint validation is based on:

• A Constraint validation HTML Input Attributes.
• A Constraint validation CSS Pseudo Selectors.
• A Constraint validation DOM Properties and Methods.

Constraint Validation HTML Input Attributes:

Attribute	Description
Disabled	Specifies that an input element should be a disabled.
Max	Specifies a maximum value of an input element.
Min	Specifies a minimum value of input element.
Pattern	Specifies a value pattern of input element.
Required	Specifies that a input field requires the element.
Type	Specifies a type of an input element.

Conclusion:

In JavaScript a forms are used to collect user’s input using various elements like input fields, check boxes, buttons, text fields, and so on. JavaScript makes it possible to process a forms without calling the server.A JavaScript provides several properties and methods to work with forms like a getElementById() method to read different HTML elements, the innerHTML property to set a form’s content and so on.This write-up offers the basic understanding of JavaScript forms with help of a suitable examples.