How to call an AngularJS Function inside HTML ?

A Function is a set of statements that takes input, does some specific computation, and produces output. In this article, we will learn How to Call an AngularJS function inside HTML. To achieve this, we can use {{…}} to call the function from HTML. We can also pass arguments and return the result back to HTML.

Steps for Installing & Configuring the Angular Application

Step 1: Create an Angular application using the following command.

ng new appname

Step 2:  After creating your project folder i.e. appname, move to it using the following command.

cd appname

Project Structure

It will look like the following:

Example 1: In this example, we will call a function from HTML. This function is written in the ts file. We will call an alert() from this function.

HTML

<!-- app.component.html -->
<h2 style="color: green">
  GeeksforGeeks
</h2>
<h2>
  How to Call an AngularJS function inside HTML
</h2>
<h3>Open your console</h3>
{{displayMessage()}}

Javascript

// app.component.ts
import { Component, OnInit } from '@angular/core';
import { KeyValue } from '@angular/common';
import { Pipe, PipeTransform } from '@angular/core';

@Component({
    selector: 'app-root',
    templateUrl: "./app.component.html",
    styleUrls: ['./app.component.css']
})

export class AppComponent {
    displayMessage() {
        console.log(
        "Hi GeeksforGeeks!! Happy Learning Angular!!")
    }
}

Javascript

// app.module.ts
import { NgModule }
    from '@angular/core';
import { BrowserModule }
    from '@angular/platform-browser';
import { HttpClientModule }
    from '@angular/common/http';
import { AppComponent }
    from './app.component';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        HttpClientModule,
    ],
    providers: [],
    bootstrap: [AppComponent]
})

export class AppModule { }

Output:

Example 2: In this example, we will see that we can pass arguments in the function, and the result will be returned by the function on the front page.

HTML

<!-- app.component.html -->
<h2 style="color: green">
  GeeksforGeeks
</h2>
<h2>
  How to Call an AngularJS function inside HTML
</h2>
<h3 style="color:crimson">
      {{displayMessage("Hi GeeksforGeeks!! Happy Learning Angular!!")}}
</h3>
<h3 style="color: darkorange;">
  Sum of 2 and 3 is :  {{getSum(2,3)}}
</h3>

Javascript

// app.component.ts
import { Component, OnInit } from '@angular/core';
import { KeyValue } from '@angular/common';
import { Pipe, PipeTransform } from '@angular/core';

@Component({
    selector: 'app-root',
    templateUrl: "./app.component.html",
    styleUrls: ['./app.component.css']
})

export class AppComponent {
    displayMessage(msg: string) {
        return msg;
    }

    getSum(a: number, b: number) {
        return a + b
    }
}

Javascript

// app.module.ts
import { NgModule }
    from '@angular/core';
import { BrowserModule }
    from '@angular/platform-browser';
import { HttpClientModule }
    from '@angular/common/http';
import { AppComponent }
    from './app.component';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        HttpClientModule,
    ],
    providers: [],
    bootstrap: [AppComponent]
})

export class AppModule { }

Output: