Code for validating forms in javascript

Posted by / 01-Oct-2016 13:04

Code for validating forms in javascript

This article assumes a general understanding of HTML and Java Script.

(16 printed pages) Introduction Getting Started Writing the Validation Script Connecting the Form to the Script Associating Form Fields with Custom Script Code Listing Conclusion When you create forms, providing form validation is useful to ensure that your customers enter valid and complete data.

The idea is to create a set of “validation descriptors” associated with each element in a form.

The “validation descriptor” is nothing but a string specifying the type of validation to be performed.

In other words if the first condition fails, the second condition will not be tested and so forth.

Only when all conditions have been satisfied do we reach the command, in which case the form will be submitted.

This tutorial will show you how to create a Java Script-enabled form that checks whether a user has filled in the form correctly before it's sent to the server. First we'll explain why form validation is a useful thing, and then build up a simple example form, explaining things as we go along.

At the end, there's a little exercise to keep you busy too!

When form input is important, it should always be verified using a secure server-side script.There are two main methods for validating forms: (usually done using Java Script).Server-side validation is more secure but often more tricky to code, whereas client-side (Java Script) validation is easier to do and quicker too (the browser doesn't have to connect to the server to validate the form, so the user finds out instantly if they've missed out that required field! In this tutorial we'll build a simple form with client-side Java Script validation.The zip file contains the javascript file, examples.The script has a catalog of almost all the common validation types built-in.

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