In Chapter 2, Creating a Simple Knockout.js Application, we examined a variety of standard Knockout.js bindings such as text, visible, click, submit, and so on. However, in a big application, this list may not be enough. Fortunately, you can define your own custom bindings.
Knockout.js provides us with the ko.bindingHandlers property to register new bindings. You can define a new subproperty of it as a JavaScript object with two callback properties: init and update. Let's take a look at the short binding registration template:
ko.bindingHandlers.newBindingName = {
init: function(element, valueAccessor, allBindings) {
// Called on first binding applying to an element
// Set up any initial state
},
update: function(element, valueAccessor, allBindings) {
// Called on first binding applying to an element and on any changing in dependences
// Update the DOM element
}
};You can apply such bindings to any DOM...