<script type="text/javascript">

 $(document).ready(function()
    {   
     jQuery.validator.addMethod("require_from_group", function (value, element, options) {
        var numberRequired = options[0];
        var selector = options[1];
        var fields = $(selector, element.form);
        var filled_fields = fields.filter(function () {
            // it's more clear to compare with empty string
            return $(this).val() != "";
        });
        var empty_fields = fields.not(filled_fields);
        // we will mark only first empty field as invalid
        if (filled_fields.length < numberRequired && empty_fields[0] == element) {
            return false;
        }
        return true;
        // {0} below is the 0th item in the options field
    }, jQuery.format("'Please enter either username/ email address to recover password'/Please fill out at least {0} of these fields."));

    var validator = $("#myForm").validate({

        groups: {
            names: "num1 num2"
        },
        rules: {                            
              num1: {
                require_from_group: [1, ".send"]
            },
            num2: {
                require_from_group: [1, ".send"]
            },                            
        },  
        errorElement: "span" ,                              
        messages: {
            name: " Enter Name",
             email: {required: "EmailId is required.",email: "Please enter the valid email address"},           
        }
    });
    if(validator.form()){ // validation perform
        $('form#myForm').attr({action: 'mycontroller'});           
        $('form#myForm').submit();
    }
 });   
</script>

    <form method="post" id="myForm" name="myForm">
    <h2 class="widgettitle2" style="margin: 13px 0px 2px 0px">Contact Us</h2>
    <p class="legend"><strong>Note:</strong> Required fields are marked with an asterisk (<em>*</em>)</p>           
    <fieldset>      
        <div><label for="name">Email<em>*</em></label> <input tabindex="1" size="40" type="text" name="num2" id="num2"  class="send_email send"/></div>
       <div><label for="Username">Username<em>*</em></label> <input tabindex="1" size="40" type="text" name="num1" id="num1" class="send_username send"/></div>    
    </fieldset> 
    <div class="buttonrow"><input tabindex="6" type="submit" class="btn" value="Submit" /> <input tabindex="7" type="button" class="btn" value="Cancel" /></div>    
</form>