access of undefined property

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

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

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

Reproduced from: Author: one pixel Www.cnblogs.com/onepixel/p/7337248.html In a recent book on "JavaScript Advanced Programming", which mentions the equality operator (= =), you cannot convert null and undefined to any other value until you compare

The data types of JavaScript are broadly divided into two categories: primitive types and Object types. Where the original type includes numbers, strings, and Boolean values. In addition, there are two special primitive values in javascript: null

The data types of JavaScript are broadly divided into two categories: primitive types and Object types. Where the original type includes numbers, strings, and Boolean values. In addition, there are two special primitive values in javascript: null

xTable of Contents [1] reason [2]undefined [3]null Front wordsGeneral programming language, which means null only, but JavaScript designer Brendan Eich design a undefined, which undoubtedly increases the complexity of the program, but there are some

The property is an attribute in the DOM, an object in JavaScript, an attribute on an HTML tag, and its value can only be a string; many friends are easily confused.analyzing property and attribute based on JavaScriptThere is such a piece of code in

Property and attribute are very easy to confuse, and the Chinese translation of two words is very similar (properties: attributes, Attribute: properties), but in fact, they are different things and belong to different categories. Property is an

Property and attribute are very easy to confuse, and the Chinese translation of two words is very similar (properties: attributes, Attribute: properties), but in fact, they are different things and belong to different categories. property