When it comes to form validation, it’s hard to have a versatile solution that works with every form. Figuring out how to display errors is not a simple task. This is something I tried to remedy with this script. When an error needs to be displayed, the script creates a div and positions it in the top right corner of the input. This way you don’t have to worry about your HTML form structure. The rounded corner and shadow are done with CSS3 and degrade well in non compliant browsers. There is no images needed.

Download the source code View demo

Validations range from email, phone, url to more complex calls such as ajax processing.
Bundled in several locales, the error prompts can be translated in the locale of your choice.

**Important**: v2 is a significant rewrite of the original 1.7 branch. Please read the documentation as the API has changed! Also the documentation is always more up to date on the github README

Legacy 1.7 documentation and download can be found under package when you hit download on github


1. Unpack the archive
2. Include the script jquery.validationEngine.closure.js in your page
3. Pick the locale of the choice, include it in your page: jquery.validationEngine-XX.js
4. **Read this manual** and understand the API

Running the Demos

Most demos are functional by opening their respective HTML file. However, the Ajax demos require the use of Java6 to launch a lightweight http server.

1. Run the script `runDemo.bat` (Windows) or `runDemo.sh` (Unix) from the folder
2. Open a browser pointing at [http://localhost:9173](http://localhost:9173)


First link jQuery to the page

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.js" type="text/javascript"></script>

Attach *jquery.validationEngine* and its locale

    <script src="js/jquery.validationEngine-en.js" type="text/javascript" charset="utf-8"></script>
    <script src="js/jquery.validationEngine.js" type="text/javascript" charset="utf-8"></script>

Finally link the desired theme

    <link rel="stylesheet" href="css/validationEngine.jquery.css" type="text/css"/>

Field validations

Validations are defined using the field’s **class** attribute. Here are a few examples showing how it happens:

    <input value="someone@nowhere.com" class="validate[required,custom[email]]" type="text" name="email" id="email" />
    <input value="2010-12-01" class="validate[required,custom[date]]" type="text" name="date" id="date" />
    <input value="too many spaces obviously" class="validate[required,custom[onlyLetterNumber]]" type="text" name="special" id="special" />

For more details about validators, please refer to the section below.


The validator is typically instantiated by using a call of the following form:

    $("#form.id").validationEngine(action or options);

The method takes one or several optional parameters, either an action (and parameters) or a list of options to customize the behavior of the engine.

Here comes a glimpse: say you have a form is this kind

    <form id="formID" method="post" action="submit.action">
        <input value="2010-12-01" class="validate[required,custom[date]]" type="text" name="date" id="date" />

The following code would instance the validation engine:




Initializes the engine with default settings

    $("#formID1").validationEngine({promptPosition : "centerRight", scroll: false});
    $("#formID1").validationEngine('init', {promptPosition : "centerRight", scroll: false});
Attaches jQuery.validationEngine to form.submit and field.blur events.
<pre lang="html">
Unregisters any bindings that may point to jQuery.validaitonEngine.
<pre lang="html">


Validates the form and displays prompts accordingly. Returns *true* if the form validates, *false* if it contains errors. Note that if you use an ajax form validator, the actual result will be delivered asynchronously to the function *options.onAjaxFormComplete*.

    alert( $("#formID1").validationEngine('validate') );

showPrompt (promptText, type, promptPosition, showArrow)

Displays a prompt on a given element. Note that the prompt can be displayed on any element an id.

The method takes four parameters:
1. the text of the prompt itself
2. a type which defines the visual look of the prompt: ‘pass’ (green), ‘load’ (black) anything else (red)
3. an optional position: either “topLeft”, “topRight”, “bottomLeft”, “centerRight”, “bottomRight”. Defaults to *”topRight”*
4. an optional boolean which tells if the prompt should display a directional arrow

       <legend id="legendid">Email</legend>
       <a href="#" onclick="$('#legendid').validationEngine('showPrompt', 'This a custom msg', 'load')">Show prompt</a>


Closes error prompts in the current form (in case you have more than one form on the page)

    $('#formID1').validationEngine('hide')">Hide prompts


Closes **all** error prompts on the page.



Options are typically passed to the init action as a parameter.
$(“#formID1”).validationEngine({promptPosition : “centerRight”, scroll: false});


Name of the event triggering field validation, defaults to *blur*.

Tells if we should scroll the page to the first error, defaults to *true*.


Where should the prompt show ? Possible values are “topLeft”, “topRight”, “bottomLeft”, “centerRight”, “bottomRight”. Defaults to *”topRight”*.

If set to true, turns Ajax form validation logic on. defaults to *false*.
form validation takes place when the validate() action is called or when the form is submitted.

onBeforeAjaxFormValidation(form, options)
When ajaxFormValidation is turned on, function called before the asynchronous AJAX form validation call. May return false to stop the Ajax form validation

onAjaxFormComplete: function(form, status, errors, options)
When ajaxFormValidation is turned on, function is used to asynchronously process the result of the validation.

Set to true when the form shows in a scrolling div, defaults to *false*.

Selector used to pick the overflown container, defaults to *””*.


Validators are encoded in the field’s class attribute, as such


Speaks by itself, fails if the element has no value. this validator can apply to pretty much any kind of input field.

    <input value="" class="validate[required]" type="text" name="email" id="email" />
    <input class="validate[required]" type="checkbox" id="agree" name="agree"/>
    <select name="sport" id="sport" class="validate[required]" id="sport">
       <option value="">Choose a sport</option>
       <option value="option1">Tennis</option>
       <option value="option2">Football</option>
       <option value="option3">Golf</option>


Validates the element’s value to a predefined list of regular expressions.

<input value="someone@nowhere.com" class="validate[required,custom[email]]" type="text" name="email" id="email" />

Please refer to the section Custom Regex for a list of available regular expressions.


Validates a field using a third party function call. If a validation error occurs, the function must return an error message that will automatically show in the error prompt.

    function checkHELLO(field, rules, i, options){
      if (field.val() != "HELLO") {
         // this allows the use of i18 for the error msgs
         return options.allrules.validate2fields.alertText;

The following declaration will do

<input value="" class="validate[required,funcCall[checkHELLO]]" type="text" id="lastname" name="lastname" />


Delegates the validation to a server URL using an asynchronous Ajax request. The selector is used to identify a block of properties in the translation file, take the following example.

    <input value="" class="validate[required,custom[onlyLetterNumber],maxSize[20],ajax[ajaxUserCall]] text-input" type="text" name="user" id="user" />
    "ajaxUserCall": {
        "url": "ajaxValidateFieldUser",
        "extraData": "name=eric",
        "alertText": "* This user is already taken",
        "alertTextOk": "All good!",
        "alertTextLoad": "* Validating, please wait"

* url – is the remote restful service to call
* extraData – optional parameters to sent
* alertText – error prompt message is validation fails
* alertTextOk – optional prompt is validation succeeds (shows green)
* alertTextLoad – message displayed while the validation is being performed

This validator is explained in further details in the Ajax section.

Check if the current field’s value equals the value of the specified field.

Validates when the field’s value if less or equal to the given parameter.

Validates when the field’s value if more or equal to the given parameter.

Validates if the element content size (in characters) is more or equal to the given *integer*. integer <= input.value.length maxSize[integer]
Validates if the element content size (in characters) is less or equal to the given *integer*. input.value.length <= integer past[NOW or a date]

Checks if the element’s value (which is implicitly a date) is earlier than the given *date*. When “NOW” is used as a parameter, the date will be calculate in the browser. Note that this may be different that the server date. Dates use the ISO format YYYY-MM-DD

    <input value="" class="validate[required,custom[date],past[now]]" type="text" id="birthdate" name="birthdate" />
    <input value="" class="validate[required,custom[date],past[2010-01-01]]" type="text" id="appointment" name="appointment" />

future[NOW or a date]

Checks if the element’s value (which is implicitly a date) is greater than the given *date*. When “NOW” is used as a parameter, the date will be calculate in the browser. Note that this may be different that the server date. Dates use the ISO format YYYY-MM-DD

    <input value="" class="validate[required,custom[date],future[now]]" type="text" id="appointment" name="appointment" /> // a date in 2009
    <input value="" class="validate[required,custom[date],future[2009-01-01],past[2009-12-31]]" type="text" id="d1" name="d1" />


Validates when a minimum of *integer* checkboxes are selected.
The validator uses a special naming convention to identify the checkboxes part of the group.

The following example, enforces a minimum of two selected checkboxes

    <input class="validate[minCheckbox[2]]" type="checkbox" name="group1" id="maxcheck1" value="5"/>
    <input class="validate[minCheckbox[2]]" type="checkbox" name="group1" id="maxcheck2" value="3"/>
    <input class="validate[minCheckbox[2]]" type="checkbox" name="group1" id="maxcheck3" value="9"/>

Note how the input.name is identical across the fields.


Same as above but limits the maximum number of selected check boxes.


We’ve introduced the notion of selectors without giving much details about them: A selector is a string which is used as a key to match properties in the translation files.
Take the following example:

    "onlyNumber": {
        "regex": /^[0-9\ ]+$/,
        "alertText": "* Numbers only"
    "ajaxUserCall": {
        "url": "ajaxValidateFieldUser",
        "extraData": "name=eric",
        "alertText": "* This user is already taken",
        "alertTextLoad": "* Validating, please wait"
    "validate2fields": {
        "alertText": "* Please input HELLO"

onlyNumber, onlyLetter and validate2fields are all selectors. jQuery.validationEngine comes with a standard set but you are welcome to add you own to define AJAX backend services, error messages and/or new regular expressions.


Ajax validation comes in two flavors:

1. Field Ajax validations, which takes place when the user inputs a value in a field and moves away.
2. Form Ajax validation, which takes place when the form is submitted or when the validate() action is called.

Both options are optional.


The client sends the form fields and values as a GET request to the form.action url.

Client calls url?fieldId=id1&fieldValue=value1&…etc ==> Server (form.action)

Server responds with a list of arrays: [fieldid, status, errorMsg].

* fieldid is the name (id) of the field
* status is the result of the validation, true if it passes, false if it fails
* errorMsg is an error string (or a selector) to the prompt text

Client receives <== [["id1", boolean,"errorMsg"],["id2", false, "there is an error "],["id3", true, "this field is good"]] Server Note that only errors (status=false) shall be returned from the server. However you may also decide to return an entry with a status=true in which case the errorMsg will show as a green prompt.


Since the form validation is asynchronously delegated to the form action, we provide two callback methods:

**onBeforeAjaxFormValidation(form, options)** is called before the ajax form validation call, it may return false to stop the request

**onAjaxFormComplete: function(form, status, json_response_from_server, options)** is called after the ajax form validation call

Custom Regex

jQuery.validationEngine comes with a lot of predefined expressions. Regex are specified as such:

<input value="" class="validate[custom[email]]" type="text" name="email" id="email" />

Note that the selector identifies a given regular expression in the translation file, but also its associated error prompt messages and optional green prompt message.

a typical phone number with an optional country code and extension. Note that the validation is **relaxed**, please add extra validations for your specific country.

49-4312 / 777 777
+1 (305) 613-0958 x101
(305) 613 09 58 ext 101
+33 1 47 37 62 24 extension 3
(016977) 1234
04312 – 777 777
+58 295416 7216

matched a url such as http://myserver.com, https://www.crionics.com or ftp://myserver.ws

easy, an email : username@hostname.com

an ISO date, YYYY-MM-DD

floating points with an optional sign. ie. -143.22 or .77 but also +234,23

integers with an optional sign. ie. -635 +2201 738

an IP address (v4) ie.

Only numbers and spaces characters

Only letters and space characters

Only letters and numbers, no space

Using the engine in a overflown div

The big change in this method is that normally the engine will append every error boxes to the body. In this case it will append every error boxes before the input validated. This add a bit of complexity, if you want the error box to behave correctly you need to wrap the input in a div being position relative, and exactly wrapping the input width and height. The easiest way to do that is by adding float:left, like in the example provided.


What would be a good library without customization ?

Adding regular expressions

Adding new regular expressions is easy: open your translation file and add a new entry to the list

    "onlyLetter": {
        "regex": /^[a-zA-Z\ \']+$/,
        "alertText": "* Letters only"

* “onlyLetter” is a sample selector name
* “regex” is a javascript regular expression
* “alertText” is the message to display when the validation fails

You can now use the new regular expression as such

<input type="text" id="myid" name="myid" class="validation[custom[onlyLetter]]"/>

Don’t forget to contribute!

Customizing the look and feel

Edit the file *validationEngine.jquery.css* and customize the stylesheet to your likings. it’s trivial if you know CSS.

Adding more locales

You can easy add a locale by taking *jquery.validationEngine-en.js* as an example.
Feel free to share the translation 😉

Rules of thumb

* field.id are **unique** across the page
* for simplicity and consistency field.id and field.name should match (except with minCheckbox and maxCheckbox validators)
* spaces or special chars should be avoided in field.id or field.name
* use lower cases for input.type ie. *text, password, textarea, checkbox, radio*
* use the Ajax validator last ie. validate[custom[onlyLetter],length[0,100],**ajax[ajaxNameCall]**]
* use only one Ajax validator per field!
* JSON services should live on the same server (or you will get into browser security issues)
* in a perfect RESTful world, http **GET** is used to *READ* data, http **POST** is used to *WRITE* data: which translates into -> Ajax validations should use GET, the actual form post should use a POST request.


Contributions are always welcome, you may refer to the latest stable project at [GitHub](https://github.com/posabsolute/jQuery-Validation-Engine)
We use [Aptana](http://www.aptana.com/) as a Javascript editor and the Rockstart JSLint & Closure plugins http://update.rockstarapps.com/site.xml


Licensed under the MIT License


Copyright(c) 2010 Cedric Dugas
v2.0 Rewrite by Olivier Refalo

If you like and use this script, please consider buying me a beer, it’s cheap and a simple way to give back!

Version 1.7.1 Online
October 20 2010, release v1.7.1: Compatibility release for jQUery 1.4.3
July 1 2010, release v1.7: div overflown support + small fix to inline ajax validation + small code overhaul
Feb 1 2010, release v.1.6.3: bugfixs from forum + exempString rule addition, update to jQuery 1.4
November 23, release v.1.6.2: bugfix script loaded via ajax,
November 23, release v.1.6.1: Refactoring, external loadvalidation() is back working, languages are now ALL loaded externally, added setting to not unbind form on success,
October 29, release v.1.6: unbind validation when success function is called, option returnIsValid added
October 27, release v.1.5: Added debug mode, event triggerer can be specified in setting and checkbox bug with cakephp corrected
September 17, release v.1.4: More frameworks support, changes with the minCheckbox and maxCheckbox
August 25, release v. Ajax submit, prompt positioning, bug correction with multiple forms
August 13, release v.1.3: Ajax validation, prompts usable outside the plugin, minor CSS corrections
July 12, release v.1.3: Validation with ids instead of name, minor CSS corrections, optional inline validation.
June 5, release v.1.2.1: Added optional validation
June 5, release v.1.2: Less error prone reg Ex, corrected an error with multiple form on the same page
June 4, release v.1.1: added date validation and select required validation, corrected errors with group radio input
June 1, release v.1.0

Comments are closed due to the overwhelming number, please use the forums for support.


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491 thoughts on “A jQuery inline form validation, because validation is a mess

  1. I love your code… definitely one of the nicest form validation bits for the client side out there. My only request would be something to enable multiple forms on the same page. For example, I’m currently giving this a test drive on my login/registration page for the registration fields but triggers when the user clicks the button to login OR register.

    Again, thank you for a great piece of code and all the work that went into it.

  2. Hello Again!

    I made another modification, because the default behavior wasn’t working for my application. Basically, I have a form with a mix of required and optional fields, all of them have this validation plug-in applied. When I would tab out of a non-required field that I left blank, the warning box would still pop up, telling me all the “rules”. This isn’t neccessary, as I only want to warn the user (for a non-required field), *if* they enter a value that doesn’t meet the required validation.

    So, I modded the JS to only show the waring box if (required == true or (required == false and field is not blank)).

    I can provide mods if desired.

    Thanks again for all your hard work on this beautiful plug-in!

    Ryan King
    Synesis, Inc.

  3. Pingback: Pascal Borreli
  4. Hey,

    thx for date and dropdown validation implementation. Great Stuff.
    One last Question: If i choose validation onlyLetter in a textfield, there is no way to type a space between 2 words. What is the regex for a space….

    PS. Sorry for my bad english, i am from germany.

  5. Hello,

    i got it:


  6. v1.2 online, space has been added in regEx and a corrected an error with multiple form on the same page

  7. @rjking I added optional validation, thank you for the idea, I did not code it the same way you did, however yours is just as good.

  8. Can i do server side validation through this ? Like email address already exist or not

  9. @Shariq, no, I guess you could modify it, but it does not listen to Ajax response.

  10. Hey there, I think I found something kind of like a bug.

    On my test site I was playing around with this AWESOME script and I was testing out the email regex. Looks pretty solid actually (if you ask me), but when I was stress testing it with the following test string:


    it went into a crazy loop and froze up my browser. Firefox says it’s line 227 – right around the regex handling stuff. Not a big deal as I doubt anyone will ever enter an email that long (Technically, they can’t be longer than 320 chars anyway), but thought you might want to try this out for yourself.

  11. @capnjeremy yeah well this is a standard regex, but I can see how the browser crashed from your pattern

  12. Hi, what I have to change if I use a “a href” button instead of normal button with type=”submit”?

  13. I guess you could add your code before I do my validation in the form submit on line 68

  14. what i have is a form that has the first and last name in the same row, and the 3 separated phone number fields. i currently am trying to write something on line 18 that checks both field one and field two.

  15. What should I do to pass my form into database using ajax.
    I’ve been following your tutorial and add some code like below but it still no data in the database.

    function callSuccessFunction(){
    type: “POST”,
    url: “ajax.php”,
    data: $(‘form#submit’).serialize(),
    success :function(){
    return false;

  16. this is not the right place, you need to follow my instruction in the ajax section

    replace “success: false,” by: success : function() { callSuccessFunction() }, and
    the right place is in the callSuccessFunction() on the index.html (this function could be anywhere)

  17. Hi, I’m having trouble making an url custom regex, it seems to have some trouble with “/” symbols, so /^(https?\/\/)/ crews up, and none of those I found on the internets worked. Mind that I’m a bit rusty on the regex part.

  18. Cedric,

    I think I have found a slight bug in the demo. In “Favorite Sport 2”, if I select “Choose a sport”, it doesn’t give me a validation tooltip.


  19. Is it possible to extend the JQuery validation plugin from ba.assistance.de with your error message display since it seems a more mature validation plugin, but your display is excellent

  20. thank you for the reply, but…I’ve actually done that. replace “success: false” and then writing the code i’ve write b4 in my index.html
    It does the ajax b’cause the form can hide and the div.success displayed. I think the one that doesn’t work is the serialize() command. Can you give me a sort example on how should I write the ajax code to pass my form into my database…?
    thanks a lot…

  21. @Stephen, I suppose someone could port it, my code is on mit licence so if anyone want to port it, fair enough

    @christopher, seems like a bug, will have a look this week.

    @stev you could try to send every input value, but serialize should work, try to send 1 input $(input#id).val() in data , and check if your php receive it. Install firebug to see what is posted, give me your email, I can send you someting you can work with tommorrow

  22. Prompts aren’t disappearing after entering fulfilling validation requirements. I’ve got a lot of javascript on this site so maybe a conflict of some sort, but I’m not able to pull any errors out of firebug. If someone had a minute to take a peak I’d appreciate it. Its a really slick validation code by the way. (sibu beauty free trial . com)

  23. facing and issur while using .net textboxes the error msg does not fade out even after entering the correct data.. where as when i replace the asp:textbox with html input boxes it works fine….

  24. your .net textboxes give what kind of html form field, textarea? what rules did you use

  25. @8asic the problem is that I use the name attribute too, this is something I will need to change in a near future

  26. For all Germans using UTF-8 you have to modify the “only letters” regex like this:

    “regex”:”/^([a-zA-ZäüöÄÜÖß\ \’]|\\s)+$/”,
    “alertText”:”* Nur Buchstaben erlaubt”}

  27. This is one great plugin, thanx for al your hard work man!

    I do have a problem with implementing it though. If you add the validation to a form inside a scrollable div (overflow), the coordinates of the ballons get messed up when you scroll. Turning the overflow of immediately fixes the issue. Point is, I have a long form inside a thickbox iframe popup (limited screen real-estate) and thus need the overflow in order to keep the buttons visible at all time.

    Any tips?

  28. How to make the message box larger ? I want to set the width to a higher value, and I don’t find where to modify the code.
    I found these lines in js/validationEngine.js
    callerWidth = $(caller).width()
    callerHeight = $(caller).height()
    inputHeight = $(divFormError).height()

    callerleftPosition = callerleftPosition + callerWidth -30
    callerTopPosition = callerTopPosition -inputHeight -10

    but here is the positioning of the message box on the screen, not the width of the message.

  29. Little bug for you: the validation doesn’t count Umlauts (äüöÄÖÜß) as letters. Very bad for international usage …

  30. beautifull validation!!!

    I am a designer/photographer… so I suck when it comes to jquery etc. I am trying to call the mail.php but I want to stay on the same page. I set the form to display none and display a message but I dont know how to continue and call the mail.php and stay on the same page.


    success : function() { $(‘#form’).hide(); $(‘p.test’).text(‘thank you’) () },,
    failure : function() { callFailFunction() }

    I would really appreciate it if someone can help me with this.


  31. @Cedric Dugas

    When trying to use this in .Net as .Net programmer says, the box does not fade out after you put something into the box and it loses focus. This is how my e-mail textbox is rendered to HTML:

    Any help is much appreciated and as has been mentioned this is the best visual implementation for client-side validation I have seen! keep up the good work!!

  32. Nope didn’t work.. last try:

    IMPUT name=”ctl10$txtEmail” type=”text” id=”ctl10_txtEmail” tabindex=”13″ class=”validate[required,custom[email]] text-input” |>>>>

  33. @Markive : As I said before I use the attribute name, unfortunately the .net framework like to temper with this attribut too. This is something I’m trying to change for v1.3

  34. Looks pretty good. You should get this up on github so the community can help with hit. Thanks

  35. hello cedric, I”ve tried to do send one input using val() to get the data and send it using $.ajax
    But, just like before…no data send to my database. Still waiting for your code in my mailbox.
    PS: Sorry for not replying again in here, coz i’m really out of internet zone. :p

  36. Great validation script. One question. Is there a way to like reset the form i.e. close all the bubbles with one click of a button or hyperlink?

Comments are closed.