javascript - Knockout.js "select all" checkboxes -

i've started playing around knockout.js, , seems cool. have grid. grid has column checkbox @ top "select all" of elements, deselect. standard grid behavior.

here's code far:

javascript:

// define "banner" class function banner(inventory, name, arttype, artsize) {     return {         isselected : ko.observable(false),         inventory : ko.observable(inventory),         name : ko.observable(name),         arttype : ko.observable(arttype),         artsize : ko.observable(artsize)      }; }  var viewmodel = {     banners : ko.observablearray([new banner("network", "banner #1"), new banner("oo", "banner #2")]),     addbanner : function() {         this.banners.push(new banner("network", "banner"));     },     selectall : function() {         this.banners.isselected(true)     }         };  ko.applybindings(viewmodel); 

i'm binding "selectall" event checkbox this:

<th><input data-bind="click: selectall" type="checkbox" /></th> 

and each individual banner have in list, checkbox looks this:

<td><input data-bind="checked: isselected" type="checkbox" /></td> 

for reason selectall function isn't working correctly. i'm new oo javascript programming paradigm, may doing blatantly wrong here.

thanks!

banners array in case, need access each item in array , update individual isselected properties.

something like:

ko.utils.arrayforeach(this.banners(), function(banner) {    banner.isselected(true); });