Minimal Math Captcha JavaScript Library – jCaptcha.js

Category: Form , Javascript | May 25, 2020
Author:robiveli
Views Total:1,757 views
Official Page:Go to website
Last Update:May 25, 2020
License:MIT

Preview:

Minimal Math Captcha JavaScript Library – jCaptcha.js

Description:

jCaptcha.js is a lightweight, vanilla JavaScript plugin that creates a simple, random, <canvas> based math captcha to protect against spam.

How to use it:

Insert the minified version of the jCaptcha.js library into the web page.

<script src="dist/index.min.js"></script>

Create an html form where you want to generate the math captcha.

<form class="form" action="">

  <input class="jCaptcha" type="text" placeholder="Type in result please">
  <button class="button" type="submit">Submit</button>

</form>

Initialize the math captcha.

var myCaptcha = new jCaptcha({

    // set callback function
    callback: function(response, $captchaInputElement) {

        if (response == 'success') {

            $captchaInputElement[0].classList.remove('error');
            $captchaInputElement[0].classList.add('success');
            $captchaInputElement[0].placeholder = 'Submit successful!';

        }

        if (response == 'error') {

            $captchaInputElement[0].classList.remove('success');
            $captchaInputElement[0].classList.add('error');
            $captchaInputElement[0].placeholder = 'Please try again!';

        }

    }

});

Validate the math captcha on form submit.

document.querySelector('form').addEventListener('submit', function(e) {

  e.preventDefault();

  // captcha validate
  myCaptcha.validate();

});

Possible options with default values.

var myCaptcha = new jCaptcha({

    // CSS class of input field
    el: 'jCaptcha',

    // character for required value
    requiredValue: '*',

    // reset on error
    resetOnError: true,

    // focus on the input on error
    focusOnError: true,

    // clear on submit
    clearOnSubmit: true,

    // CSS class of canvas
    canvasClass: 'jCaptchaCanvas',

    // canvas styles
    canvasStyle: {
      width: null,
      height: null,
      font: '',
      fillStyle: '',
      textAlign: '',
      textBaseline: ''
    }

});

Changelog:

v1.3.0 (05/25/2020)

  • Updated options
  • Resolved issue with multiple instances
  • Code improvements
  • Drop support for IE10

01/02/2020

  • Update

11/13/2018

  • Minor updates

05/28/2018

  • v1.1.0

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2 thoughts on “Minimal Math Captcha JavaScript Library – jCaptcha.js

  1. NB

    Hi, I downloaded, but files are missing, where is jCaptcha.min.js ?

    Reply

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