object undefined

Object constructor to create a wrapper. Grammar Object initializer (initialiser) or object literal (literal) {[namevaluepair1[, namevaluepair2[, ... ... Namevaluepairn]]]} // Call new Object in constructor form ([value]) Parameters NameValuePair1

1. Object Mode varo1 {}; literal representation form varo2newObject; varo3newObject (); varo4newObject (null); varo5newObject (undefined); varo6Object. c... 1. Object Mode Var o1 = {}; // literal representation var o2 = new Object; var o3 = new

Tag (space separation) variable 1. Variable variable is a container for storing book values; JavaScript Learning Tags (separated by spaces) variables 1. What is a variable?A variable is a container that stores book values; 2. Game RulesVariable

Reprinted from: http://blog.sina.com.cn/s/blog_6154bf970101jam7.htmlWith web development today, jquery is almost essential, and even the VS artifact has been built into the jquery and UI Web projects in version 2010. As for the use of jquery

Merging of objectsRequirements: With Object O1, O2, need to get objects O3var O1 = {A: ' A '}, O2 = {b: ' B '}; then var O3 = {A: ' A ', B: ' B '}Method 1: Use the Extend method of jquery* * Method definition **:jquery.extend ([deep], Target, Object1

You may know that the type of object in JS can be judged by typeof. Look at the situation below.From the above we can see that the array and the ordinary objects are judged by the TypeOf is object, but now we have this requirement, we have to

This and javascriptthis in JavaScript The topic here is this. This itself was originally very simple and always pointed to the current instance of the class. this cannot be assigned a value. This premise is that this cannot be separated from classes/

JQuery static method type usage and source code analysisJQuery. the type method is a tool method for detecting data types. Before analyzing its usage, summarize the methods that js provides for us to monitor data types; i. below is the test code var

Referenced from: http://www.cnblogs.com/eoiioe/archive/2008/12/31/1366081.html Both instanceof and typeof can be used to determine whether a variable is empty or what type of variable it is. typeof is used to get the type of a variable, typeof

1. The main difference between null and undefined in JScript is that the operation of NULL is like the number 0, while the operation of undefined is like a special value Nan (not a number). The comparison of null values and undefined values is

About types What is a type? Simply put, a type is to assign a binary sequence in the memory to some meaning. For example, binary Sequence 0100 0000 0111 0000 0001 0101 0100 1011 1100 0110 1010 0111 1110 1111 1001 if it is regarded as a 64-bit

Original http://blog.csdn.net/mashangyou/article/details/24036233You may know that the type of object in JS can be judged by typeof. Look at the situation below.From the above we can see that the array and the ordinary objects are judged by the

This article mainly introduces $ in jQuery. extend () usage. The example analyzes the functions, definitions, and related usage skills of the extend () method. if you need it, refer to the example in this article to describe $ in jQuery. extend ()

This in JavaScript is always confusing and should be one of the well-known pitfalls of js. I personally think this in js is not a good design. Due to the late binding feature of this, it can be a global object, the current object, or... Some people

Open the book and enter the world of JavaScript. Used to look at all kinds of video, feel what harvest has not, but make brain confusion, hope to follow the rhythm of this book to master JavaScript this language, for my front-end learning lay the

This in JavaScript is always confusing and should be one of the well-known pitfalls of js. I personally think this in js is not a good design. Due to the late binding feature of this, it can be a global object, the current object, or... Some people

Catalog [1]typeof [2]tostring [3]constructor] [4]instanceoftypeofThe typeof operator is used to return a type that is using a value"Output" lowercase string as the first letterfunction[1] The standard type can be recognized (recognizes null as

Recently saw a lot of ways to judge data types, summed up the nextOne, JavaScript data typesThere are two types of JS data: raw data type and reference data type .raw data Types are: string, number, Boolean, Undefined, and nullreference data Types

Note: arrays in JavaScript are not associated arrays. In JavaScript, only objects are used to manage key-value mappings. However, the associated array maintains the order, but the object is not.Because the for in loop will enumerate all attributes

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