apply()方法、call()方法都能劫持另外一个对象的方法,继承另外一个对象的属性
一、apply()方法
Function.apply(obj,args)
- obj:这个对象将代替Function类里 this 对象, 即 this 本来是指向Function的,现在为指向 obj 的;
- args:这个是数组,它将作为参数传给Function(args–>arguments)
var person = {
fullName: function() {
return 'fullName = ' + this.firstName + " " + this.lastName;
}
}
var student = {
firstName: "Bill",
lastName: "Gates",
}
person.fullName.apply(student); // 将返回 "Bill Gates"
var person = {
fullName: function(city, country) {
return 'fullName = ' + this.firstName + " " + this.lastName + ";address = " + city + "," + country;
}
}
var student = {
firstName:"John",
lastName: "Doe"
}
person.fullName.apply(student , ["Oslo", "Norway"]);
二、call()方法
Function.call(obj,arg1,arg2…)
- obj:这个对象将代替Function类里 this 对象, 即 this 本来是指向Function的,现在为指向 obj 的;
- arg1/arg2:它将作为参数传给Function(arg–>argument)
var person = {
fullName: function(city, country) {
return 'fullName = ' + this.firstName + " " + this.lastName + ";address = " + city + "," + country;
}
}
var student = {
firstName:"John",
lastName: "Doe"
}
person.fullName.call(student, "Oslo", "Norway");
三、call() 和 apply() 之间的区别
call() 方法 “分别” 接受参数。
apply() 方法接受数组形式的参数。
如果要使用数组而不是参数列表,则 apply() 方法非常方便。