Customizable Form Validator With Native JavaScript – js-form-validator.js

An easy-to-use yet fully customizable form field validator built using native JavaScript with no 3rd JavaScript libraries.

Predefined validation rules:

• notzero
• integer
• float
• name
• lastname
• phone
• email
• min
• max
• between
• length
• minlength
• maxlength
• maxfilesize
• fileextension

How to use it:

Import the main JavaScript file ‘js-form-validator.min.js’ into your html file.

<script src="js-form-validator.min.js"></script>

Apply the validation rules to the target form fields using data-rule attributes. You can apply multiple rules to the same field by separate the rules with ‘|’.

<form name="form" id="myForm">
  <input type="text" name="email" data-rule="required|email">
  <input type="text" name="email" data-rule="required|phone">
  ...
  <input type="submit" value="Submit">
</form>

Initialize the library and done.

new Validator(document.querySelector('#myForm'), function (err, res) {
    return res;
});

Add your own validation rules and error messages:

new Validator(document.querySelector('#myForm'), function (err, res) {
    return res;
},options: {
    rules: {
      custom: function (value) {
        return (value.trim().toLowerCase() === 'custom');
      }
    },
    messages: {
      en: {
        custom: {
          incorrect: 'Error ;-)'
        }
      }
    }
  };
);

More default settings.

// Validation of a current field after the events of "change", "keyup", "blur"
onAir: true,
// Show validation errors
showErrors: true,
// Auto-hide the error messages
autoHideErrors: false,
// Timeout auto-hide error messages
autoHideErrorsTimeout: 2000,
// Language error messages
locale: 'en',
// Object for custom error messages
messages: {},
// Object for custom rules
rules: {},
// classname for error messages
errorClassName: 'error',
// remove spaces from validation field values
removeSpaces: false,
// tracking of new elements
autoTracking: true,
// events list for binding
eventsList: ['keyup', 'change', 'blur']

Changelog:

10/21/2018

• Now, if the field is marked as REQUIRED, the validator looks for the next rule for this field and displays its text in the error class.