knockout.js - How to access knockout viewmodel from javascript -

i trying understand how manage scope in javascript code. once create viewmodel, how access rest of javascript? (last line in code generates 'not defined' error

note: have found several posts on differences between function/var ko, none have said there scoping advantage using var... have tried both methods.

//function appviewmodel() { //    this.gridsize = ko.observable("30"); //    this.canvaswidth = ko.observable("600"); //    this.canvasheight = ko.observable("600"); //    this.displaycoords = "axial"; //    this.pixel="0"; //    this.hex="0"; //} //ko.applybindings(new appviewmodel());  var appviewmodel = {     gridsize: ko.observable("30"),     canvaswidth: ko.observable("600"),     canvasheight: ko.observable("600"),     displaycoords: "axial",     pixel:"0",     hex:"0" }; ko.applybindings(appviewmodel );  var test = appviewmodel.gridsize; 

ko.observable function , reference observable value have have brakets

e.g. example above

var test = appviewmodel.gridsize(); 

found explanation http://knockoutjs.com/documentation/observables.html