knockout js variable overide
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I have some global variables in my script:

	var yardsToFirst = 10;
	var yardsToTD = 80;
	var exactDown = 1;

In my ViewModel I take in and modify the variables. According to Google Chrome's javascript  console the variables are being modified. I try to have them observed so they can update the UI like this:

	self.down = ko.observable(exactDown);
	self.toGo = ko.observable(yardsToFirst);
	self.toGoal = ko.observable(yardsToTD);

It all works fine right when I load the page. The problem comes when I start modifying the data. the UI never changes. I have checked and the javascript console says the global variables hold the correct numbers but still the UI is not updated. Am I doing something that is impossible or have I go about it the wrong way?