Kayoval

Kayoval customizes your HTML5 validation by extending your Knockout view models.

Here's a quick example:

<input data-bind="value: password" type="password" required="required" />
<input data-bind="customValidation: true, value: confirmPassword" type="password" />

viewModel.password = ko.observable().extend({
    customValidation: {
        message: "You must enter a password."
    }
});
 
viewModel.confirmPassword = ko.observable().extend({
    customValidation: {
        mustMatch: viewModel.password,
        message: "Your passwords must match."
    }
});

Right now we just have the mustMatch validation rule, but it's very pluggable if you can think of other rules! And you can use message independently of mustMatch, so even if you just want a different error message for the required attribute (or pattern, or whatever), we've got you covered!

Usage

Kayoval is packaged as a Node.js module, meant for use with a system like Browserify.