JavaScript

I do not know my JS level how, but today a bit hit, see a lot of problems have pits. After reading some interview questions, I recorded the pits I met today.Issue 1: ScopeConsider the following code, what is the output?(functionvar a = b = 5;}) ();

One, the size of the Web page and the size of the browser windowFirst, there are two basic concepts to be clarified.The whole area of a webpage is its size. Typically, the size of a Web page is determined by the content and CSS style sheets.The size

JavaScript instanceof and typeof are commonly used to determine whether a variable is empty, or what type it is. But there is a difference between them:First, typeof1, meaning: typeof returns a string of the data type of an expression, and returns

Scripting of JavaScript classes Defining variables and methods internally The this declaration is used to define common public properties and public methods In the internal var declaration, or simply do not write Var (implicitly

In JavaScript, the function's this keyword behaves a lot differently than other languages. There is also a slight difference between the strict and non-strict modes of JavaScript.In most cases, the way the function is called determines the value of

The definition of a policy pattern is to define a series of algorithms, seal them up and make them interchangeable.JavaScript version of the policy mode:Bonus system:varStrategies = { "S":function(Salary) {returnSalary*4; },

The inheritance mechanism of the JavaScript language, which does not have the concept of "subclass" and "parent class", nor the distinction between "class" and "instance" (instance), it relies on a very peculiar "prototype chain" (prototype chain)

Closures (closure) are a very important threshold for mastering JavaScript from the human door to the deep, which is a difficult and characteristic of the JavaScript language, and many advanced applications rely on closures. Below, write down my

Button not availableButton can not be used disabled not be able to use the meaningbtn.disabled = "Disabled" | | Btn.disabled = true;GreyAttention: Because the button is a double label, you want to change his value, using InnerHTML, not

The so-called simple factory pattern is a way to decide exactly which instance of the class to create, and these instances often have the same interface. Simple Factory mode mainly use a few situations (add personal Understanding) 1, the

Experience Summary of jQuery parallax scrolling effect webpage implementation method, jquery Parallax This article summarizes and analyzes the implementation of jQuery parallax scrolling effect web pages. We will share this with you for your

Summary of several javascript writing methods and several javascript writing methods several JavaScript The above is all the content of several javascript writing methods provided by xiaobian. I hope it will be helpful to you and

JavaScript closure details, javascript details A deep understanding of JavaScript-closures Like many new users, I am also the frontend. It takes a lot of time and effort to understand closures. The results are also good. Today I will explain the

The applet runs on the Chrome browser and uses WebStorm, chromewebstorm The development framework of "mini-programs" is quite good-it comes with the UI framework. But the problem is that his IDE is quite bad-in fact, it was mainly because I had

Applet (2) detailed introduction to Window configuration, Applet window Window is used to set the status bar, navigation bar, title, and background color of the applet. Note that the property configured in app. json overwrites the window property.

Applet (9) scroll-view component details, Applet scroll-view Scroll-view is a rolling view, divided into horizontal and vertical scrolling. Note that you must set the height when scrolling the view vertically. Otherwise, scroll-view will not take

Applet (16) form component details, Applet form The form component submits the values of all selected attributes in the form. Note that each component in the form must have the name attribute specified. Otherwise, the component cannot be submitted.

Chrome determines whether to click the label on the input to implement other labels. chromeinput Function to be implemented: when the input box is out of focus and the key is not cleared, run the reset method to reset the input style. When you click

JavaScript learning notes _ about expressions and statements, javascript learning notes Expressions and statements Eval () has only one parameter If the parameter is not a string, this parameter is directly returned; When the parameter is a string,

Details about how Node. Js processes post data, and details about node. jspost Implementation Put the callback functions of the data and end events directly on the server, and collect all POST data in the data Event Callback. After receiving all