1-3KO.html

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<p>Enter a numeric value:<input data-bind="value: attemptedValue"/></p>
		<div data-bind="visible: !lastInputWasValid()">That's not a number!</div>
	</body>

	<script type='text/javascript' src='js/knockout.js'></script>

	<script>
		
		var ViewModel = function() {
			this.acceptNumberValue = ko.observable(123);
			this.lastInputWasValid = ko.observable(true);
			this.attemptedValue = ko.computed({
				read:this.acceptNumberValue,
				write:function(value) {
					if(isNaN(value)) {
						this.lastInputWasValid(false);
					} else {
						this.lastInputWasValid(true);
						this.acceptNumberValue(value);
					}
				},
				owner:this
			});
			
		};
		
		//实例化一个viewModel
		var currentViewModel = new ViewModel();
		
		ko.applyBindings(currentViewModel);

		
		
		
	</script>
</html>