Question

When using knockout 2.2.0 with a dropdown box in IE8 we are getting an error. In IE 8 the length of the array is shown as 2 instead of 1. It works fine in IE9 and above and other browsers.

I’ve put the code in this fiddle.

The UI code looks like:

<script>
   function EmailDomain(text, value) {
       this.DisplayText = text;
       this.Value = value;
   }
   function VM(){
       self.EmailDomains = ko.observableArray([
            new EmailDomain("aaa.com", "aaa.com"),
        ]);

       self.SelectedEmailDomain = ko.observable(self.EmailDomains()[0]);
   }
</script>

<select data-bind="options: EmailDomains, optionsText: 'DisplayText', value: SelectedEmailDomain"></select>

Answer 1

Haven’t had a chance to test this yet as I don’t have IE8 on this machine, but it might be because you have an accidental comma at the end of your array that isn’t necessary?

self.EmailDomains = ko.observableArray([
    new EmailDomain("aaa.com", "aaa.com") // Removed: ,
]);

IE does some crazy things when there are commas out of place so its worth a try!