jQuery Validation Plugin

Demo:

Usage:

Wrap all required fields in .required-field class (can be a div, a span, a p or any element) and apply the validation function to the form

$("#myform").submit(function () {
	return $(this).validation(); //returns true or false
});

Demo HTML:

<form action="" method="post" id="myform"> 
	<fieldset>
		<legend>Registration</legend>
		<div class="required-field">
			<label for="firstname">First Name</label>
			<input type="text" name="firstname" id="firstname" />
		</div>
		<div class="required-field">
			<label for="lastname">Last Name</label>
			<input type="text" name="lastname" id="lastname" />
		</div>		
		<div class="required-field">
			<label for="username">Username</label>
			<input type="text" name="username" id="username" />
		</div>		
		<div class="required-field">
			<label for="email">Email</label>
			<input type="text" name="email" id="email" />
		</div>	
	</fieldset>
</form>

Download:

jquery.validation.js