a js function that displays validation error messages from an object whose structure matches that returned by Zend\Form\Form::getMessages()

display_validation_errors.js

displayValidationErrors = function(validationErrors) {
    $('.validation-error').empty();
    for (var field in validationErrors) {
        //console.log("examining field "+field);
        for (var key in validationErrors[field]) {
            // console.log("examining key "+key);
            var message = validationErrors[field][key];
            var element = $('#' +field);
            var errorDiv = $('#error_'+field);
            if (! errorDiv.length) { errorDiv = null;}
            if (! element.length) { console.log("is there no element #"+field+ " ?");
                // look for an existing div by id
                if ($('#error_'+field).length) {
                    $('#error_'+field).html(message);
                } else {
                    console.warn("no element with id "+field + ", and nowhere to put message "+message);
                }
            } else {
                errorDiv = errorDiv || element.next('.validation-error');
                if (! errorDiv.length) {
                    errorDiv = $('<div/>')
                            .addClass('alert alert-warning validation-error')
                            .attr({id:'error_'+field})
                    .insertAfter(element);
                }
                errorDiv.html(message).show();
            }
            break;
        }
    } 
};