Validate with a function

/**
*
* Example 1 (pattern validation)
*
*/
var poBox = function (val) {
     var poPattern = /[P|p]*(OST|ost)*\.*\s*[O|o|0]*(ffice|FFICE)*\.*\s*[B|b][O|o|0][X|x]/,
     regexPO = new RegExp(poPattern);
    
     if (regexPO.test(val)) {
         return "PO box not allowed";
     }

     return true;

 }

 $('#ex1_address1')
     .isNameField({
     validateWith: poBox,
     required: true,
     requiredMessage: "Address Name is required",
     message: "Enter your Address"
 });
 $('#ex1_address2')
     .isNameField({
     validateWith: poBox,
     required: true,
     requiredMessage: "Address Name is required",
     message: "Enter your Address"
 });



 $("#frmRegistration").validateForm();

Change options after form initialization

     /**
     * Example 2 (changing options after form validation)
     */
     //initialize fields
     $('#ex2_fname').isNameField({ required : true, requiredMessage : "First Name is required", message : "Enter your First Name"});
     $('#ex2_lname').isNameField({ required : true, requiredMessage : "Last Name is required", message : "Enter your Last Name"});

     //setup form
     $('#frmExampleTwo').validateForm();

    
     //checkbox to require only last name
     $('#ex2_requireLastNameOnly').click(function(){
        if($(this).val()==="on"){
            //set first name requirement to false
            $('#ex2_fname').isNameField('setOption','required',false)
        }
     })