A very simple yet configurable error/hint message system for form validation.position:absolute so it doesn't affect your html layout.

Curently support validations(for input and textarea):

1.jquery 1.11 (or maybe smaller, you could try)

Is there anything better than an real example? No, so let's start here:

<form enctype="multipart/form-data" method="post">
  <table>
    <tr>
      <td><label for="id_username">账号</label></td>
      <td><input id="id_username" name="username" type="text" /> </td>
    </tr>
    <tr>
      <td><label for="id_password">密码</label></td>
      <td><input id="id_password" name="password" type="password" /> </td>
    </tr>
  </table>
  <input type="submit" value="提交"/>
</form> 

1.add jquery, validators.css and validators.js to your html page (like home.html).

2.config form_fields object in validators.js like this(hint or validators are optional):

var form_fields = {
  username :{
    hint       : 'enter your username(2 chars at least, 10 at most)', 
    validators : [required, min_len(2), max_len(10)]
  }, 
  password :{
    validators : [required, regex(/^[\da-zA-Z@$_!-]{6,32}$/)]
  }, 
}

Above code means that :
1)username and password are required.
2)When you in username, a green hint message enter your username(2 chars at least, 10 at most) will show.
3)There must be 2 characters at least and 10 at most in username.

What if a input is not required, but you still want some validations when user offer value? you need to add not_required.like:

validators : [not_required,  min_len(2), max_len(10)]

3.enjoy it.