clickでCSS変更

<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<title>clickでCSS変更</title>
<script type="text/javascript" src="jquery-1.5.1.min.js"></script>
<script type="text/javascript" src="knockout-2.1.0beta.js"></script>
<script type="text/javascript">
$(document).ready(function () {
function viewModel() {
var self = this;
self.changeColor = ko.observable(0);
self.ClickChangeColorA = function() {
self.changeColor(1);
};
self.ClickChangeColorB = function() {
self.changeColor(-1);
};
}
ko.applyBindings(new viewModel());
});
</script>
<style type="text/css">
.test{
color:red;
}
</style>
</head>
<body>
<h1>clickでCSS変更</h1>
<div data-bind="css: {'test': changeColor() < 0}">
てすと
<button data-bind="click: ClickChangeColorA">無指定</button>
<button data-bind="click: ClickChangeColorB">赤くする</button>
</div>
<div style="font-size:10pt;text-align:right;margin-top:0.5em;">
<a href="//tips.recatnap.info/" target="_top">PCスキルの小技・忘却防止メモ</a> -
<a href="//tips.recatnap.info/wiki/" target="_top">PCスキルの小技・忘却防止メモのまとめ（wiki）</a>
</div>
<div style="font-size:10pt;text-align:center;margin-top:0.5em;padding:0.5em;border-top:1px solid #ccc;">
</div>
</body>
</html>