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Detailed explanation of the difference between constructors with parentheses and without parentheses
Detailed explanation of the difference between constructors with parentheses and without parentheses
This article mainly brings you a detailed discussion of the difference between constructors with parentheses and without parentheses. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor to take a look, I hope it can help everyone.
As shown below:
//首先定义一个构造函数Hello
function Hello（）{
alert（1）；
}
//定义一个函数表达式
var getName = function（）{
alert（2）；
}
//实例化对象，下面这两个如果构造函数没有形参的话，实例化的时候构造函数可以不加括号（推荐加上）；
var p = new Hello；
var p1 = new Hello（）；
//但是用下边的方式调用getName函数的时候，构造函数有没有括号可就不一样了；
new Hello.getName（）； //这种执行顺序是先执行Hello.getName（），然后在使用new关键字；
new Hello（）.getName；//这种是先new Hello（）一个对象，然后对象调用getName方法；Related recommendations:
Detailed explanation of class, constructor, and factory functions in Javascript
Java overloading, rewriting, and constructor details
Detailed introduction to this and return in JavaScript constructors
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