5.1.3 对Function扩展
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2023-12-01
| Method | Kind | Arguments | Description |
| bind(object) | instance | object: the object that owns the method | 返回function的实例，这个实例和源function的结构一样，但是它已被绑定给了参数中提供的object，就是说，function中的this指针指向参数object。 |
| bindAsEventListener(object) | instance | object: the object that owns the method | 用法和上面的bind一样，区别在于用来绑定事件。 |
让我们看看如何运用这些扩展。
<input type=checkbox id=myChk value=1> Test?
<script>
//declaring the class
var CheckboxWatcher = Class.create();
//defining the rest of the class implementation
CheckboxWatcher.prototype = {
initialize: function(chkBox, message) {
this.chkBox = $(chkBox);
this.message = message;
//assigning our method to the event
this.chkBox.onclick =
this.showMessage.bindAsEventListener(this);
},
showMessage: function(evt) {
alert(this.message + ' (' + evt.type + ')');
}
};
var watcher = new CheckboxWatcher('myChk', 'Changed');
</script>