Custom Form Validation

Form validation is fundamental for most web applications. Of course, front-end form validation alone isn’t effective without back-end form validation, but front-end form validation gives the user quick feedback without waiting for the back-end response.

HTML5 form validation

Since the introduction of HTML5, client-side form validation has become simple. Basic client-side form validation doesn’t require JavaScript anymore. In addition, any invalid field will automatically prevent a form submit. We can implement HTML5 validation with up to seven different attributes:

• required: This is utilized if an element needs a value at all.
• type: This is a general indicator of the type of data (number, email password, etc.).
• minlength: This is the minimum length of the input.
• maxlength: This is the maximum length of the input.
• min: This is the minimum numeric value of the input.
• max: This is the maximum numeric value of the input.
• pattern: This is a regular expression the value is matched against.

Arguably, the most flexible ...