 <p>Correct...and to launch you even further, check out this modification. </p> <p><a href="http://jsfiddle.net/Fv27b/2/" rel="nofollow">http://jsfiddle.net/Fv27b/2/</a></p> <p>Here, you'll see that not only are we combining the options, but we're creating our own binding entirely...which results in a much more portable extension of not just this view model, but any view model you may have in your project...so you'll only need to write this one once!</p> <pre><code>ko.bindingHandlers.colorAndTrans = { update: function(element, valAccessor) { var valdata = valAccessor(); var cssString = valdata.color(); if (valdata.transValue() &lt; 10) cssString += " translucent"; element.className = cssString; } } </code></pre> <p>To invoke this, you just use it as a new data-bind property and can include as many (or as few) options as possible. Under this specific condition, I might have just provided $data, however if you're wanting a reusable option you need to be more specific as to what data types you need as parameters and not all view models may have the same properties.</p> <pre><code>data-bind="colorAndTrans: { color: color, transValue: number }" </code></pre> <p>Hope this does more than answer your question!</p>