Learn Angular in simple step by step
- AngularJS is a JavaScript framework. It can be added to an HTML page with a <script> tag.
- AngularJS extends HTML attributes with Directives, and binds data to HTML with Expressions.
- AngularJS is a JavaScript framework. It is a library written in JavaScript.
- AngularJS is distributed as a JavaScript file, and can be added to a web page with a script tag:
AngularJS Expressions
AngularJS expressions can be written inside double braces:
{{ expression }}.
AngularJS expressions can also be written inside a directive:
ng-bind="expression".
AngularJS will resolve the expression, and return the result exactly where the expression is written.
AngularJS expressions are much like JavaScript expressions: They can contain literals, operators, and variables.
Example {{ 5 + 5 }} or {{ firstName + " " + lastName }}
Example
<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<body>
<div ng-app="">
<p>My first expression: {{ 5 + 5 }}</p>
</div>
</body>
</html>
If you remove the
ng-app directive, HTML will display the expression as it is, without solving it:Example
<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<body>
<div>
<p>My first expression: {{ 5 + 5 }}</p>
</div>
</body>
</html>
You can write expressions wherever you like, AngularJS will simply resolve the expression and return the result.
Example: Let AngularJS change the value of CSS properties.
Change the color of the input box below, by changing its value:
Example
<div ng-app="" ng-init="myCol='lightblue'">
<input style="background-color:{{myCol}}" ng-model="myCol">
</div>
AngularJS Numbers
AngularJS numbers are like JavaScript numbers:
Example
<div ng-app="" ng-init="quantity=1;cost=5">
<p>Total in dollar: {{ quantity * cost }}</p>
</div>
Same example using
ng-bind:Example
<div ng-app="" ng-init="quantity=1;cost=5">
<p>Total in dollar: <span ng-bind="quantity * cost"></span></p>
</div>
Using
ng-init is not very common. You will learn a better way to initialize data in the chapter about controllers.AngularJS Strings
AngularJS strings are like JavaScript strings:
Example
<div ng-app="" ng-init="firstName='John';lastName='Doe'">
<p>The name is {{ firstName + " " + lastName }}</p>
</div>
Same example using
ng-bind:Example
<div ng-app="" ng-init="firstName='John';lastName='Doe'">
<p>The name is <span ng-bind="firstName + ' ' + lastName"></span></p>
</div>
AngularJS Objects
AngularJS objects are like JavaScript objects:
Example
<div ng-app="" ng-init="person={firstName:'John',lastName:'Doe'}">
<p>The name is {{ person.lastName }}</p>
</div>
Same example using
ng-bind:Example
<div ng-app="" ng-init="person={firstName:'John',lastName:'Doe'}">
<p>The name is <span ng-bind="person.lastName"></span></p>
</div>
AngularJS Arrays
AngularJS arrays are like JavaScript arrays:
Example
<div ng-app="" ng-init="points=[1,15,19,2,40]">
<p>The third result is {{ points[2] }}</p>
</div>
Same example using
ng-bind:Example
<div ng-app="" ng-init="points=[1,15,19,2,40]">
<p>The third result is <span ng-bind="points[2]"></span></p>
</div>
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