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Learning Dart

Learning Dart

4.4 (10)
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Learning Dart

Learning Dart

4.4 (10)

Overview of this book

Mastering Dart by Projects is a step-by-step guide that aims to give you hands-on knowledge about programming in Dart using an example-based approach.If you want to become a web developer, or perhaps you already are a web developer but you want to add Dart to your tool belt, then this book is for you. This book assumes that you have at least some knowledge of HTML and how web applications work. Some previous programming experience, preferably in a modern language like C#, Java, Python, Ruby, or JavaScript, will also give you a head start. You can also work with Dart on your preferred platform, be it Linux, Mac OS X, or Windows.
Table of Contents (14 chapters)
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13
Index

Spiral 2 – how to validate data with Dart


If you have tested the Spiral 1 – the power of HTML5 forms version thoroughly, you would have come across some things that could be improved:

  1. The HTML5 control only does its checks when the Create Account button is clicked on; it would be better if the user is alerted earlier, preferably after filling in each field.

  2. The Birth Date value is checked to be a correct DateTime value, but a value in the future is accepted.

  3. The Gender field will gladly accept other values than M or F.

  4. The Balance field accepts a negative number.

So HTML5 doesn't give us full validation possibilities; to remedy and supplement that, we must add code validation, see bank_terminal_s2.dart:

Note

For code files of this section, refer to chapter 6\bank_terminal_s2 in the code bundle.

InputElement name, address, email, birth_date, gender;
InputElement number, balance, pin_code;
void main() {
  // bind variables to DOM elements:
  name = querySelector('#name');
  address = querySelector...

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