JavaScript

Native JavaScript traversal 1, for loop traversal1 Let array1 = [' A ', ' B ', ' C ']; 2 3 for (Let i = 0;i ) {4 console.log (Array1[i]); // a b 5 }2. JavaScript provides a foreach () map () Two ways to iterate over an array objectThe foreach

There are 6 types of data in ECMAScript, including 5 basic data Types (undefined,null,boolean,number,string) and a complex data type (Object). "ES6 adds a more symbol data type, but it's not a discussion here first."Undefined typeThe undefined type

Arr. arraysNew arraySTR-stringsModify Location Index--Modified Quantity NItem-Modified Content"1" Array additions1, index in turn increaseArr.push (' item ');Put item2. Start adding ' item ' at the specified indexArr.splice (index, 0, ' item ');The

The 1.javascript engine works by parsing the code, getting all the declared variables, and then running on one line, which results in the declaration of all variables being promoted to the head of the code, which is called the elevation of the

One, "no block-level scope in JavaScript"There are block-level scopes in Java and C #, which is: curly braces are also a scopevoid Main () { if(1==1) { = "Seven"; } SYSTEM.OUT.PRINTLN (name);} // ErrorJavavoid Main () { if(1==1) {

1. Convert a string to a variable name[JavaScript]View PlainCopyPrint? function  string_to_name (String) {       let _name =  ' var new_name= ' +STRING;    eval (_name);       return  _name;   } 2. Convert a string to a

Directory The concept of closures Talking about function execution environment, scope chain and variable object Closures and Function currying Extra memory footprint due to closures (note I'm not talking about "memory leaks"!) ）

First, constructor inheritance　　The simplest approach is to use the call or Apply method to bind the parent object's constructor to the child object.functionParent (name) { This. Name =name; This. color = [' red ', ' green ']; This. GetInfo

Identifiers undefined do not really reflect "undefined" because undefined is not a JavaScript reserved wordJavaScript provides an void operator that evaluates the specified expression and returns the trusted undefined :void expression It is obtained

? far greater than symbolsIn the mathematical formula, ">>" stands for greater than the symbol, indicating that one number is much larger than another, such as 76>>3,-2>>-99. Poincaré and Borel first used it in 1901, and was soon accepted by the

First ,JavaScript introduction1. What is JavaScript?JavaScript is a literal-translation scripting language, which is a dynamic type, a weak type, a prototype-based language, and a built-in support type. Its interpreter, known as the JavaScript

Use JavaScript to do intermittent scrolling of textCONST INIT = (InitData) ={Const area=Initdata.area;//sets the height of the single-line scrolling;Const Ilineheight = initdata.ilineheight? Initdata.ilineheight:24;//set the speed of scrolling;Const

closures (closure) are a difficult and unique feature of the JavaScript language, and many advanced applications rely on closures. Here is my study note, which should be useful for JavaScript beginners.The scope of a variableTo understand closures,

1. Arraysvar arr = array ();Can specify the number, or do not specify, or directly fill in the parameters using "," separatedor use the [] declaration directly, var arr = ["Nane", 0,false]And you can do that.arr["name"] = 0; Actually more like the

JavaScript mouse Follow effects lang= "en" > CharSet= "UTF-8" >

Object, which is a very important stem in JavaScript, is a good understanding of how it is directly related to your basic understanding of the entire JavaScript system, which is, in plain parlance, a group of objects. Beep ）。Several common types of

Null has no property value and cannot get its entity (existence) value. So Null.property returns an error instead of a undefined.Consider the following codeif (Node.nextSibling.className = = ...) {...}If node or node.nextsibling is empty (null), an

How to input two text boxes at the same time to implement two text boxes How to input two text boxes at the same time  

How to write the css series button and cssbutton In the development of the modern front-end industry, if you haven't used some pre-compilation tools while using css, do you think you are too low. But have you considered building your own front-end

For how to upload and preview images in html, Local Image Preview Method 1   Method 2