email
...
### Explaining the DOM
First, obviously, there is a Form element with the novalidate attribute to make sure to disable the native HTML5 validations (which currently suck). proceeding it there is a Fieldset element which is not a must, but acts as a “binding” box for a group of fields that are under the same “category”. For bigger forms there are many times field groups that are visually separated from each other for example. Now, we treat every form field element the user interacts with, whatsoever, as an “item”, and therefor these “items” will be wraped with ``. This isolation gives great powers.
Next, inside an item, there will typically be an input or select or something of the sort, so they are put inside a `` element, to get rid of the (annoying) for attribute, on the label (which also require us to give an ID to the form field element), and now when a user clicks on the label, the field will get focused. great. Going back to the label’s text itself, we wrap it with a `` to have control over it’s style.
The whole approach here is to define each form field (input, select, whatever) as much as possible with HTML5 attributes and also with custom attributes.
**required attribute**
Defines that this field should be validated (with JS by my implementation and not via native HTML5 browser defaults)
**placeholder attribute**
Writes some placeholder text which usually describes the fields with some example input (not supported in IE8 and below)
**data-validate-words custom attribute**
Defines the minimum amount of words for this field
**data-validate-length custom attribute**
Defines the length allowed for the field (after trim). Example value: “7,11″ (field can only have 7 or 11 characters). you can add how many allowed lengths you wish
**data-validate-length-range custom attribute**
Defines the minimum and/or maximum number of chars in the field (after trim). value can be “4,8″ for example, or just “4″ to set minimum chars only
**data-validate-linked custom attribute**
Defines the field which the current field’s value (the attribute is set on) should be compared to
**data-validate-minmax custom attribute**
For type ‘number’ only. Defines the minimum and/or maximum value that can be in that field.
**data-validate-pattern custom attribute**
Defines a pattern which the field is evaluated with. Available values are:
*numeric* - Allow only numbers
*alphanumeric* - Allow only numbers or letters. No special language characters
*phone* - Allow only numbers, spaces or dashes
aleternativly, you can write your own custom regex here as well.
### Optional fields
There is also support for optional fields, which are not validated, unless they have a value. The support for this feature is done by adding a class “optional” to a form element. Note that this should not be done along side the “required” attribute.
## Error messages
The validator function holds a messages object called ‘message’, which itself holds all the error messages being shown to the user for all sort of validation errors.
message = {
invalid : 'invalid input',
empty : 'please put something here',
min : 'input is too short',
max : 'input is too long',
number_min : 'too low',
number_max : 'too high',
url : 'invalid URL',
number : 'not a number',
email : 'email address is invalid',
email_repeat : 'emails do not match',
password_repeat : 'passwords do not match',
repeat : 'no match',
complete : 'input is not complete',
select : 'Please select an option'
};
This object can be extended easily. The idea is to extend it with new keys which represent the name of the field you want the message to be linked to, and that custom message appear as the ‘general error’ one. Default messages can be over-ride.
Example: for a given type ‘date’ field, lets set a custom (general error) message like so:
`validator.message['date'] = 'not a real date';`
Error messages can be disabled:
`validator.defaults.alerts = false;`
## Binding the validation to a form
There are 2 ways to validate form fields, one is on the submit event of the form itself, then all the fields are evaluated one by one. The other method is by binding the ‘checkField’ function itself to each field, for events like “Blur”, “Change” or whatever event you wish (I prefer on Blur).
###Example - 1
A generic callback function using jQuery to have the form validated on the “Submit” event. You can also include your own personal validations before the **checkAll()** call.
$('form').submit(function(e){
e.preventDefault();
var submit = true;
// you can put your own custom validations below
// check all the rerquired fields
if( !validator().checkAll( $(this) ) )
submit = false;
if( submit )
this.submit();
return false;
})
###Example - 2
Check every field once it looses focus (onBlur) event (using jQuery 1.7.1 new ‘on’ method which is like the old .deligate() in this case).
$('form').on('blur', 'input[required]', validator().checkField);
## Tooltips
The helper tooltips **<div class='tooltip help'>**, which work using pure CSS, are element which holds a small **'?'** icon and when hovered over with the mouse, reveals a text explaining what the field “item” is about or for example, what the allowed input format is.
## Bonos – multifields
I have a cool feature I wrote which I call “multifields”. These are fields which are often use as to input a credit card or a serial number, and are actually a bunch of input fields which are “connected” to each other, and treated as one. You can see it in the demo page, and it’s included in ‘multifield.js’ file.