Knockout.js 'valueInit' binding (initialize value from html markup)

gistfile1.coffee

  ko.bindingHandlers.valueInit =
    init: (element, valueAccessor) ->
      property = valueAccessor()
      if !ko.isWriteableObservable(property)
        throw new Error 'Knockout "valueInit" binding expects an observable.'
      property element.value


#html example
#<input data-bind="value: message, valueInit: 'Hello world'" />