jQuery ValidationEngine: How to validate that at least one of a set of fields is not empty?

Question

In our project we are using ValidationEngine, and we don't have the ability to replace it with another plug-in.

Our form has ten inputs and some of them are optional, but at least one of the optional fields must be included.

So, how do you validate inputs in this case?

Sample:

form
  input1
  input2
  intpu3

input1: required

At least one of input2 and input3 must be present -- if both are empty validation should fail.

Answer 1

The validation engine now supports group Validation.Go to jQuery form validation plugin @ github and ake a look at groupRequired. The syntax looks something like this.

<input value="" class="validate[groupRequired[payments]]" type="text" name="creditcard" id="creditcard" />
<input class="validate[groupRequired[payments]]" type="text" id="paypal" name="paypal"/>

Answer 2

It appears that the ValidationEngine plugin allows you to specify a validation rule which uses a custom function to determine validity.

If you add the validate class on input1 like so...

<input id="input1" class="validate[required,funcCall[myValidationFunction]]" />

Then ValidationEngine will use the following function. You can pretty much put any kind of logic in there. If I read your scenario correctly, this should accomplish what you're after.

function myValidationFunction() {
  var input1 = $.trim($("#input1").val());
  var input2 = $.trim($("#input2").val());
  var input3 = $.trim($("#input3").val());

  if (input1.length == 0) {
    return "input1 is required";
  }

  if (input2.length == 0 && input3.length == 0) {
    return "Either input2 or input3 is required";
  }

  // We don't need to return anything if there is no error.
}

Here's a link to the _funcCall function in the source code: https://github.com/posabsolute/jQuery-Validation-Engine/blob/master/js/jquery.validationEngine.js#L574