ecmascript tutorial

to the mathematical Convention, when the array is empty, some directly returns false, every directly returns True,So when designing to a feature business, you need to be aware of this, and it's best to add a qualification to ensure that the array is not empty and that the code is intended to be read more clearly.At the same time, it is understood from the specification that, as with logic and similarity, when one of the judgments returns false, the entire calculation stops directly, returning t

[Node. js] Generator and koa Analysis in ECMAScript 6I 've heard from you that koa is a good method. I 've also caught up with it in the past two days: I installed node 0.11.12 with n, and I got a koa to start the harmony mode and try it out. In a series of documents and posts, we probably realized that koa is a new-generation Web framework dominated by corner stone. koa's middleware is based on ES6 generator functions (function *) the core process li

concatenated using a locale-specific delimiter to form a string.13, Unshift () adds one or more elements to the beginning of the array and returns the new length.14. The ValueOf () method returns the original value of the Array object.Iii. SummaryThere are several main methods of array:1, increase Concat (): Adds one or more elements, modifies the array directly, and returns the new array. Push (): Adds 1 or more elements to the end of the array, returning a new array length. U

code after the loop continues to execute (if any)Example: Continue Results: 12346789Break Results: 1234　　Five, exception statementtry { //This piece of code runs from top to bottom, where any one of the statements throws an exception the code block ends running}catch (e) { ///If an exception is thrown in a try code block, the code in the catch code block is executed. //e is a local variable that is used to point to an Error object or other thrown object}finally {//Whether or not the co

returns a reference to the array function that created this object.In the JavaScript language, the constructor property is specifically designed for function, and it exists in the prototype attribute of each function. This constructor holds a reference to the function. When defining a function (as shown in the code below),function F () {//Some code}? The following actions are performed inside JavaScript: adding a prototype (i.e., prototype) property to the function? Add an extra constructor pro

syntax is as follows: Copy Code code as follows: With (expression) { Statement } Usage examples: Copy Code code as follows: var smessage= "Hello World"; With (smessage) { Console.log (toUpperCase ());//hello World } Switch statement The sister statement of the IF statement is a switch statement. The switch syntax is as follows: Copy Code code as follows: switch (expression) { Case value1: Statement Break Case valu

2.1 Grammar Case sensitive, variable weak type, end-of-line semicolon optional, comment double slash, bracket indicates code block 2.2 Variables Variables are declared with VAR, the variable's naming rule: the first character must be a letter, an underscore, or a dollar sign; the remaining characters can be underscores, dollar signs, or any letter or numeric character. Variable Naming conventions: Camel notation: The first letter is lowercase, and the next word begins with an uppercase letter

Object Initialization (English Source: ECMAScript-262 Fifth Edition) (Huang Di for commentary or vacancy)中文版 Object initialization is an expression that describes the initialization process of an object in a direct amount of terms. It is a list of 0 or more pairs of attribute name/association values enclosed in curly braces, and values do not need to be direct, and they are executed once each time the object initialization is executed. Grammar: ob

access to the memory location, that is, the object can not directly manipulate the memory space, when manipulating the object, is actually a reference to the manipulation object and not the actual object. The value of a reference type is accessed by reference. So changing one of these variables will affect the other.var obj1 = new Object ();var obj3 = new Object ();var obj2 = obj1;Obj1.name = "JEWL";Obj3.name = "Kancy";Console.log (obj1.name);//"JEWL"Console.log (Obj2.name); "Jewl"Obj1 = obj3;C

case of an empty array, so according to the mathematical Convention, when the array is empty, some directly returns false, every directly returns True,So when designing to a feature business, you need to be aware of this, and it's best to add a qualification to ensure that the array is not empty and that the code is intended to be read more clearly.At the same time, it is understood from the specification that, as with logic and similarity, when one of the judgments returns false, the entire ca

. The new array opens up a new set of memory storage data and does not establish a view on top of the original array's memory.If you want to change the original set structure synchronously in the traversal operation, there is no direct method, but there are two kinds of iterations. One is to use the original set structure to map out a new structure, and then assign to the original set structure, the other is the use of the Array.from method In Tips:map, only a reference to the same obje

[cagkey] = Cagvalue; }} OB = new Proxy (ob, pro); ob.like = ' man ';The function defined within the set will be triggered automatically when the listener changes, and the 3 values in the parameter list are defined by default, in order: the modified object, the object's key, and the object's value.It is important to note that if you trigger a listener for an element, its original modification process will be blocked (if you do not take this step), so we need to explicitly modify it.The results

Note:And othersProgramDifferent design languages, ecmascript does not verify whether the number of parameters passed to the function is equal to the number of parameters defined by the function. All functions defined by the developer can accept any number of parameters (a maximum of 25 parameters can be accepted according to Netscape documentation) without causing any errors. Any missing parameters will be passed to the function as undefined, and addi

point number. For example:VaR inum1 = 25;VaR inum2 = ~ Inum1;Alert (inum2); // outputs "-26"(2) boolean operatorLogic not !, Logical and , logical or |(3) Relational operatorsVaR bresult = "brick" Alert (bresult); // outputs "true" // character of B andCodeThey are 66 and 97, respectively. VaR bresult = "23" Alert (bresult); // outputs "true"VaR bresult = "23" Alert (bresult); // outputs "false" // This is because when the string "23" is compared with the number, the string is converted to th

:' + ouser. get_email () + // '\ Nlogin name:' + ouser. get_loginname (); // Alert (userinfo ); Clientcontext. Load (ouser ); Clientcontext.exe cutequeryasync (function. createdelegate (this, this. onquerysucceededaddusertosharepointgroup ), Function. createdelegate (this, this. onqueryfailedaddusertow.pointgroup )); } Function onquerysucceededaddusertow.pointgroup (){Alert (this. ouser. get_title () + "added .");}Function onqueryfailedaddusertow.pointgroup (sender, argS ){Alert ('request faile

Using the ecmascript object model, we can copy or move files in the documentlist. Here, we need to achieve the effect that when a document in the document list is selected, a button appears in its associated ribbon area. Click this button, you can copy the selected document or move it to another document list. As follows: Here we areCodeSpecifies the name of the target document list. In actual operations, you can click the button to bring up t

In the default ribbon of SharePoint document list, there is such a send email button, through which you can share the selected document to other users, such: However, in the sent email, the default email button uses the URL address of the document to send, instead of the unique document ID provided by Sharepoint, the most obvious disadvantage of sharing a document with a document URL is that once we move this document, this URL becomes invalid, users who have shared this document will not b

statements or continue statements. Break and continue statements Both break and continue provide stricter control over the code execution in the loop. The break statement can immediately exit the loop, while the continue only exits the current loop and enters the next loop. Example:Copy codeCode: var iNum = 0;For (var I = 1; I If (I % 5 = 0 ){Break;}INum ++;}Console. log (iNum); // 4 INum = 0;For (var I = 1; I If (I % 5 = 0 ){Continue;}INum ++;}Console. log (iNum); // 8 INum = 0;Outer: // tagFo

This section mainly introduces ECMAScript, a main component of javascript. Download I am a resultionist. I only recognize the results and do not recognize the process. A single goal and a task can be completed by me, that is, coding, however, I don't have the need for expression, and I don't pay much attention to theories (maybe many like-minded friends). I want to change myself after I change my job in a city. My career direction is. net softwar

Previously we mentioned how to use the ecmascript object model to operate ordinary list items. But if the list we operate contains a lookup field, what should we do?First, refer to this article to build our testing environment.SharePoint Study Notes --- splist -- create a list with the lookup field 1. For the get operation, we use the followingCode The effect is as follows: 2. For the modification operation, we use the following code: The