jQuery Custom Validation Rule – fieldPresent

This post shows you how to add a custom validation rule to your forms using the jQuery.validate.js plugin. This post supports the Setup form validation using jQuery in just 2 minutes post. I used the $.validator.addMethod() function to setup the custom validation rules. I’ve added a Live Demo below.

Update: 30/06/2013: Added custom validation rule for date of birth.

Examples

The example below shows a custom validation rule which checks that both a name and email are present. If the name is present the email must be present and vice versa.

Example on left field validation.

Example on right field validation.

Example on both in action on multiple pairs.

Live Demo

Edit in jsfiddle

JQUERY

There is a patched version of this snippet at the end of the post, which fixes some cross browser and validation recursion issues.

$.validator.addMethod("fieldPresent", function (value, element, options)
{
    //we need the validation error to appear on the correct element
    var targetEl = $('input[name="'+options.data+'"]'),
        bothEmpty = (value == targetEl.val() == '');

    //trigger error class on target input
    (bothEmpty) ? targetEl.addClass('error') : targetEl.removeClass('error');
    return !bothEmpty;
},
    "Friend's name and email required."
);

$('#myForm').validate({
    onkeyup: true,
    rules: {
        "friend1-name": { "fieldPresent": { data: "friend1-email" } },
        "friend1-email": { "fieldPresent": { data: "friend1-name" } }             
    },
    submitHandler: function(form) {

        console.log('passed validation.');
        //submit form handler
    }
});

HTML

    

        Friend's name
        

            
        
    
    

        Email Address
        

            
        
    

CSS

.control-group {
    width: 100%;
}

.control-group-inner {
    width: 50%;
    float: left;
    display: inline-block;
}

If the jQuery code snippet above doesn’t work here is a newer version to remove some bugs. Kind of want to avoid setTimeouts as they are bad coding practice…

//custom validation: each friend entered must have an email and a name
$.validator.addMethod("fieldPresent", function (value, element, options)
{
    //we need the validation error to appear on the correct element
    var targetEl = $('input[name="'+options.data+'"]'),
        targetEmpty = (targetEl.val() == ''),
        elEmpty = (value == ''),
        bothEmpty = elEmpty && targetEmpty;

    //trigger error class on target input
    if (!bothEmpty && targetEmpty)
    {
        //error msg doesn't exist yet so wait...
        setTimeout(function()
        {
            if (targetEl.closest('.control-group-inner').find('label.fieldPresentError').length == 0)
            {
                targetEl.addClass('error');
                if (!elEmpty) $(element).closest('.control-group-inner').find('label.fieldPresentError').remove();
                targetEl.closest('.control-group-inner').find('label.fieldPresentError').remove();
                targetEl.after("Friend's name and email required.");
            }
        }, 500);
    }

    return (bothEmpty || !elEmpty);
},
    "Friend's name and email required."
);

Validate Date of Birth (3 inputs)

How to validate dob which contains 3 inputs for day, month & year. You’ll need to add a custom validation rule.

//custom validation for dob
$.validator.addMethod("dobValid", function (value, element, options)
{
    //we need the validation error to appear on the correct element
    var day = $('input[name="dob-day"]'),
        month = $('input[name="dob-month"]'),
        year = $('input[name="dob-year"]'),
        anyEmpty = ( day.val() == '' || month.val() == '' || year.val() == '' );

    if (anyEmpty) {
        day.add(month).add(year).addClass('error');
    }
    else {
        day.add(month).add(year).removeClass('error');
    }

    return !anyEmpty;
},
    "Please enter your date of birth."
);


...


$form.validate({
    rules: {

        ...

        "dob-year": { required: "required", dobValid: true }

        ...

    },
    messages: {

        ...

    },
    submitHandler: function(form) {

        ...
        
    }
});