listenTo
优质
小牛编辑
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2023-12-01
描述 (Description)
它告诉对象在另一个对象上侦听事件。 它会跟踪事件并在事件发生时提供回调函数。
语法 (Syntax)
object.listenTo(other, event, callback)
参数 (Parameters)
other - 它定义另一个对象的名称。
event - 它绑定一个对象。
callback - 它是对代码的引用。
例子 (Example)
<!DOCTYPE html>
<html>
<head>
<title>Event Once Example</title>
<script src = "https://code.jquery.com/jquery-2.1.3.min.js"
type = "text/javascript"></script>
<script src = "https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js"
type = "text/javascript"></script>
<script src = "https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js"
type = "text/javascript"></script>
</head>
<body>
<script type = "text/javascript">
// Create an object 'myVal' and 'myVal1' and extend them using Backbone.Events method
var myVal = _.extend({name:'Hello..'}, Backbone.Events);
var myVal1 = _.extend({name:'Welcome to xnip!!!'}, Backbone.Events);
// create the 'listenMe' callback function and invoke when one object
// listens to particular event on another object
var listenMe = function() {
document.write("The value is: ");
document.write(this.name);
};
// The object 'myVal1' listens once for the 'listenMe' event triggered on object 'myVal'
myVal1.listenTo(myVal, 'listenMe', listenMe);
// The 'myVal' has no listenMe event and displays the value of 'myVal1'
myVal.trigger('listenMe');
</script>
</body>
</html>