how to show an image loading spinner with knockout.js

Question

I'm using knockout to bind a list of images. What's the best way to set up a spinner background while the images are loading. I have a spinner class I can set and unset to the background image, but wondering if there is an easy way to bind to image complete events with knockout.js.

Answer 1

using jquery UIs little spinner thing, I have a binding handler like

 ko.bindingHandlers.Loading = {
        update: function (element, valueAccessor, allBindingsAccessor) {
            var value = valueAccessor(), allBindings = allBindingsAccessor();
            var valueUnwrapped = ko.utils.unwrapObservable(value);

            if (valueUnwrapped == true)
                $(element).showLoading(); // Make the element visible
            else
                $(element).hideLoading();   // Make the element invisible
        }
    };

and then use it like

<div data-bind="Loading: isLoading" >

so, basically, you can bind it to anything on your view model that might represent its loading ( or busy ) or not.