captcha angular 9

Addcaptcha

Creating a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) in Angular 9 involves several steps. In this example, we'll demonstrate how to implement a simple CAPTCHA using Angular 9 and TypeScript. The CAPTCHA will consist of a random mathematical expression that the user needs to solve to prove they are human.


1. Set up an Angular 9 project:
If you haven't already, create a new Angular 9 project using the Angular CLI:


```bash

ng new captcha-app

cd captcha-app

```


2. Generate a new component for the CAPTCHA:
Create a new component that will display the CAPTCHA expression and handle the user's input:


```bash

ng generate component captcha

```


3. Implement the CAPTCHA logic in the captcha.component.ts file:


```typescript

import { Component, OnInit } from '@angular/core';


@Component({

selector: 'app-captcha',
templateUrl: './captcha.component.html',
styleUrls: ['./captcha.component.css']

})

export class CaptchaComponent implements OnInit {

captchaExpression: string;
userAnswer: number;
isCaptchaValid: boolean = false;


ngOnInit() {

this.generateCaptcha();

}


generateCaptcha() {

const operand1 = Math.floor(Math.random() 10) + 1; // Random number between 1 and 10
const operand2 = Math.floor(Math.random() 10) + 1;
const operator = Math.random() < 0.5 ? '+' : '-'; // Randomly select addition or subtraction


this.captchaExpression = `${operand1} ${operator} ${operand2}`;

}


checkCaptcha() {

// Evaluate the expression to get the expected result

const expectedAnswer = eval(this.captchaExpression);


// Check if the user's answer matches the expected result

this.isCaptchaValid = this.userAnswer === expectedAnswer;


// Generate a new CAPTCHA after each attempt (optional)

this.generateCaptcha();

this.userAnswer = null;

}

}

```


4. Implement the CAPTCHA template in captcha.component.html:


```html


Prove you are human!


Solve the following CAPTCHA:

{{ captchaExpression }} =





CAPTCHA successfully solved!




```


5. Add some basic styling in captcha.component.css (optional):


```css

div {

border: 1px solid #ccc;
padding: 20px;
width: 300px;
margin: 0 auto;

}


input {

margin-bottom: 10px;

}


button {

cursor: pointer;

}

```


6. Include the captcha component in your app.module.ts file:


```typescript

import { NgModule } from '@angular/core';

import { BrowserModule } from '@angular/platform-browser';

import { FormsModule } from '@angular/forms';


import { AppComponent } from './app.component';

import { CaptchaComponent } from './captcha/captcha.component';


@NgModule({

declarations: [AppComponent, CaptchaComponent],
imports: [BrowserModule, FormsModule],
providers: [],
bootstrap: [AppComponent]

})

export class AppModule {}

```


7. Add the captcha selector to your app.component.html file:


```html


```


8. Finally, run your Angular 9 application:


```bash

ng serve

```


Now, when you access your Angular app in the browser, you'll see a simple CAPTCHA with a randomly generated mathematical expression. Users need to solve the expression correctly to prove they are human. If they get it right, a success message will be displayed, and a new CAPTCHA will be generated for the next attempt.


Please note that this example is a basic implementation of CAPTCHA for demonstration purposes. In a real-world scenario, you would want to enhance the CAPTCHA's complexity and security to make it more robust against automated attacks.