Book Image

HTML5 Data and Services Cookbook

Book Image

HTML5 Data and Services Cookbook

Overview of this book

HTML5 is everywhere. From PCs to tablets to smartphones and even TVs, the web is the most ubiquitous application platform and information medium bar. Its becoming a first class citizen in established operating systems such as Microsoft Windows 8 as well as the primary platform of new operating systems such as Google Chrome OS. "HTML5 Data and Services Cookbook" contains over 100 recipes explaining how to utilize modern features and techniques when building websites or web applications. This book will help you to explore the full power of HTML5 - from number rounding to advanced graphics to real-time data binding. "HTML5 Data and Services Cookbook" starts with the display of text and related data. Then you will be guided through graphs and animated visualizations followed by input and input controls. Data serialization, validation and communication with the server as well as modern frameworks with advanced features like automatic data binding and server communication will also be covered in detail.This book covers a fast track into new libraries and features that are part of HTML5!
Table of Contents (21 chapters)
HTML5 Data and Services Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Validating text by length


One of the most basic checks at the client side is the length of the text being inserted or submitted with the form. This is often left out, but it is one of the checks that must be done and not just at the client side. Imagine if we had no restriction on any of our inputs, a few large texts could overload the server without making much effort.

How to do it...

Let's create a simple HTML form that will contain a few different inputs on which we will apply some constrains:

  1. Head of the page is a standard one, so we will directly go into creating the form, first adding the name input limited to 20 characters as follows:

    <form>
        <div>
          <label>
            Name <input id="name" type="text" name="name" maxlength="20" title="Text is limited to 20 chars"placeholder="Firstname Lastname" >
          </label>
        </div>
  2. After that we will add another input field that initially has an invalid value, longer than the one specified for testing purpose...