validation - decorateElement

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/knockout-validation/1.0.2/knockout.validation.min.js"></script>
<form data-bind='submit:OnSubmit'>
    <input data-bind="value: name" />
    <input type='submit' value='submit' />
<form>

CSS

.validationElement { background-color:red; }

JavaScript

ko.validation.configure({ decorateElement: true });

function vm(){
    var self = this;
    self.name = ko.observable("Bob").extend({ required:true });
    self.OnSubmit = function(){
        self.errors.showAllMessages();         
    };

    ko.validation.group(self);
}

ko.applyBindings(new vm());