This is the Lesson #9 in the "AngularJS: From 0 To 100" articles written for Beginners. This lessons start at Lesson #1 .
<<<< PREVIOUS LESSON NEXT LESSON >>>>
Here we're using the "Brackets" free web Editor , which support for AngularJS Apps : see more in this post.
Our AngularJS App will be shown this way :
HTML5 Forms, Data Validation and Error Messages in AngularJS
First of all, we declare an Angular App by referencing the AngularJS framework :
(copy-paste):
<!doctype html>
<html data-ng-app="MusicApp">
<head>
<title>
AngularJS Forms Validation
</title>
<link href="Controllers.css" rel="stylesheet" type="text/css" />
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.7/angular.min.js"></script>
<script src="Controllers.js" type="text/javascript"></script>
</head>
Then we add the AngularJS View from the previous Lesson #8 :
(copy-paste):
<div class="centered">
<h1>Fragile State Discography</h1>
<h2>Neil Cowley (Zero 7) and Ben Mynott</h2>
</div>
<div id="controls1" data-ng-controller="MusicController">
<ul >
<li data-ng-repeat="album in albums">
.{{$index + 1}}
<img src="{{album.img}}" alt="{{album.name}}" >
<span >{{album.name}} - {{album.price | currency:"USD$" | uppercase}}</span> </li>
</ul><br />
</div>
</body>
</html>
In the javascript file, add the Controller as follows:
We just populated the albums list. Browse to check if its OK:
Next, append the HTML5 form as follows:
Now add the Controller method as follows:
(copy-paste):
var oMusicApp = angular.module('MusicApp', []);
oMusicApp.controller('MusicController', [ '$scope', function ($scope) {
var albums =
[
{id:111,img:"Nocturnal.jpg",name:"Nocturnal Beats",price:"12.50"},
{id:112,img:"Facts.jpg",name:"The Facts And The Dreams",price:"11.20"},
{id:113,img:"Voices.jpg",name:"Voices From The Dust Bowl",price:"13.70"},
{id:114,img:"Pretz.jpg",name:"Soundcastles",price:"14.80"}
]
$scope.albums = albums;
$scope.submitForm = function() {
console.log('Your Purchase Order : ', $scope.order);
};
}]);
Next, we append an HTML5 form with two input elements, and using the AngularJS data-ng-submit directive for calling the Controller's "submitForm()" method on form submit:
(copy-paste):
<form data-ng-submit="submitForm()" name="PurchaseForm">
Your email <br />
<input type="email" name="userEmail" data-ng-model="order.Email" > <br />
Item's quantity<br />
<input type="number" name="quantity" min="1" data-ng-model="order.Quantity" >
<br />
<input type="submit" value="Send" >
</form>
Browse to your App to check whether everything's fine:
Now we need to add a "select" element, bound to the "ID" property of an inner "album" object in the "Order" (that's why the data-ng-model will be "order.album.id" ):
The data-ng-options directive tells to the AngularJS engine to add an "option" element for each "album in albums", and to set as value the "album.id" property, and as text , the "album.name + album.price" properties chained.
(copy-paste):
Selected Album<br />
<select data-ng-model="order.album.id"
data-ng-options="album.id as album.name +'($'+album.price+')' for album in albums"
required>
</select><br />
Browse and refresh the app:
Open the Developers Tools ( F12 ) and see the Console:
You can see the "Order" object and its properties, including the "album" object.
But, what if the user clicks the Submit button with no data at all?:
In this case, the "Order" object will be undefined.
Therefore, let's add Data Validation to our form:
We just tell Angular to disable the "Submit" button if the form is "$invalid", that in our case means that at least one of the three input elements is empty, or that the Email length is shorter than 8.
(copy-paste):
<form data-ng-submit="submitForm()" name="PurchaseForm">
Your email <br />
<input type="email" name="userEmail" data-ng-model="order.Email"
required data-ng-minlength="8" >
<br />
Item's quantity<br />
<input type="number" name="quantity" min="1" data-ng-model="order.Quantity" required>
<br />
Selected Album<br />
<select data-ng-model="order.album.id"
data-ng-options="album.id as album.name +'($'+album.price+')' for album in albums"
required>
</select><br />
<input type="submit" value="Send" data-ng-disabled="PurchaseForm.$invalid">
</form>
Refresh the web page, and test it:
If the album has not been selected, then the "submit" button will be disabled.
Select an album:
It works fine, but the User has no clue why the button is not enabled. We must add Error messages to the web form, as follows:
We declare here, that if the Email is invalid, or shorter than 8, or has not been provided, then the corresponding Errors should be shown . Same thing for the Quantity.
(copy-paste):
<form data-ng-submit="submitForm()" name="PurchaseForm">
Your email <br />
<input type="email" name="userEmail" data-ng-model="order.Email"
required data-ng-minlength="8" >
<span data-ng-show="PurchaseForm.userEmail.$error.required" class="errorMessage">
*
</span>
<span data-ng-show="PurchaseForm.userEmail.$invalid" class="errorMessage">
Please type a valid Email
</span>
<span data-ng-show="PurchaseForm.userEmail.$error.minlength" class="errorMessage">
(Minimum length 8)
</span><br />
Item's quantity<br />
<input type="number" name="quantity" min="1" data-ng-model="order.Quantity" required>
<span data-ng-show="PurchaseForm.quantity.$error.required" class="errorMessage">
* Please select a value
</span> <br />
Selected Album<br />
<select data-ng-model="order.album.id"
data-ng-options="album.id as album.name +'($'+album.price+')' for album in albums"
required>
</select><br />
<input type="submit" value="Send" data-ng-disabled="PurchaseForm.$invalid">
</form>
Refresh the web page:
Now the User can know why the input is illegal. If we type a valid email, the error message will be gone:
Entering all required fields will therefore enable the Submit button:
If you liked the CSS3 style, here you have the code to copy:
div[id^=controls]{padding:5px 5px 5px 25px;margin:10px 15px 15px 25px;font:900 12px Comic Sans MS;opacity:0.9;background:#fed; border:10px solid #ddd; border-radius: 10px;box-shadow:10px 10px 2px #c0c0c0;}button,input[type=submit] {padding:5px 5px 5px 5px;margin:10px 15px 15px 15px;width:220px;text-align: center;background:#ddd; font:900 14px Comic Sans MS;opacity:0.9;border:1px solid #c0c0c0; border-radius: 10px;box-shadow:10px 10px 2px #c0c0c0;}ul{list-style:none; }input {padding:5px 5px 5px 5px;margin:10px 15px 15px 15px;width:150px;text-align: center;background:#fea; font:900 12px Comic Sans MS;opacity:0.9;border:7px solid #ddd; border-radius: 10px;box-shadow:10px 10px 2px #c0c0c0;}select{padding:5px 5px 5px 5px;margin:10px 15px 15px 15px;width:250px;text-align: center;background:#fea; font:900 12px Comic Sans MS;opacity:0.9;border:1px solid #fe9; border-radius: 10px;box-shadow:10px 10px 2px #c0c0c0;}div.centered{ text-align:center }.errorMessage{ color:red; }}
<<<< PREVIOUS LESSON NEXT LESSON >>>>
Enjoy AngularJS.....
by Carmel Schvartzman
כתב: כרמל שוורצמן
No comments:
Post a Comment