Client-side Form Validation

Provide feedback to users prior to submitting form.

• Native browser functionality with HTML5 form controls (see MDN: Client-side form validation)
  • form0.html
• DIY (Do It Yourself) or RYO (Roll Your Own) with JS
• JS libraries — some are 'plain' JS based (e.g. Pristine), others with jQuery (e.g. jQuery Validation Plugin).