javascript return false if undefined

False, zero, null, undefined, and empty string objects in Javascript In Javascript, We often come into contact with the five special objects mentioned in the question -- false, 0, empty string, NullAnd undefined. These objects are easy to use

In JavaScript, we are often exposed to the 5 more special objects mentioned in the topic--false, 0, empty strings, null, and undefined. These objects are easy to use, so you have to be careful when you use them.Type detectionLet's come down and see

When discussing the raw data types in JavaScript, most people know the basics from string, number to Boolean. These primitive types are fairly simple and behave in a common sense. However, this article will focus more on the unique raw data types

In JavaScript, we are often exposed to the 5 more special objects mentioned in the topic-false,0, empty strings ,null , and undefined . These objects are easy to use, so you have to be careful when you use them.Type detectionLet's come down and see

In JavaScript, we are often exposed to the 5 more special objects mentioned in the topic--false, 0, empty strings, null, and undefined. These objects are easy to use, so you have to be careful when you use them.Type detectionLet's come down and see

In JavaScript, we are often exposed to the 5 more special objects mentioned in the topic--false, 0, empty strings, null, and undefined. These objects are easy to use, so you have to be careful when you use them.Type detectionLet's come down and see

When discussing the primitive data types in Javascript, most people know the basic knowledge, from String, Number to Boolean. These primitive types are quite simple and behavior is common sense. However, this article will focus more on the unique

Most computer languages have and have only one value that denotes "none", such as the nil of the None,ruby language of the Null,python language of the C language Null,java language. Oddly enough, the JavaScript language actually has two values that

Article Author: TyanBlog: noahsnail.com |  CSDN | Jane book 1. The return value of JavaScript The return values in JavaScript are grouped into four categories: Return return false; return true; return variable (variable); These four return values

When discussing the primitive data types in JavaScript, most people know the basic knowledge, from String, Number to Boolean. These primitive types are quite simple and behavior is common sense. However, this article will focus more on the unique