How can I filter (only the ones changed) the list of objects postback from an editor template?

I've added a property to my model IsValueChanged false by default. I keep this is a hidden field on my view. In my editor template I have

@Html.TextBoxFor(m => m.SassVar, new { @onchange = "{@Model.IsValueChanged = true}"})

Unfortunately when inspecting the page after load all these values are true.

I also tried writing some js script but it doesn't execute, i guess it has something t do with the fact that is an editor template.. please help