


IE image cache document.execCommand('BackgroundImageCache',false,true)_javascript skills
The Pixy method is affected by IE's cache bug and will flicker. In fact, this problem is not clearly stated, but in fact the bug is conditional, that is, IE's cache is set to Every visit to the page, rather than the default Automatically. Basically, only developers will set the cache to check for updates every time they are accessed, so this bug will not actually affect real users (according to the test under winxpsp2 and ie6, although the network access api may still be called, but No actual request occurs. The symptom is that the mouse jitters for a very short time, but the image does not flicker). In addition, someone found an undisclosed method to let IE cache the background image: document.execCommand("BackgroundImageCache",false,true)
Using this method even avoids api calls, and it seems to be cached directly in IE memory. middle.
The background image set under IE6 will not be cached. Even if the server is cached, if you want to cache it, it can only be cached~~~
People who have done UI design and development must As you know, IE (excluding IE7) will often reload the background image from the server, and the good UI interface is being tossed in IE (excluding IE7)...
Erik discovered A simple solution (valid for IE below IE7, in fact, this bug has been fixed in IE7)
Program code
document.execCommand("BackgroundImageCache", false, true);
I found Jack while reading the source code of Ext today. Slocum has taken this into consideration and provided its implementation in Ext.js. There should be no such similar code in other Ajax frameworks. From this detail, we can see the comprehensiveness of Ext~
Program code
var isIE = ua.indexOf(" msie") > -1, isIE7 = ua.indexOf("msie 7") > -1;
// remove css image flicker
if(isIE && !isIE7){
try{
document.execCommand("BackgroundImageCache", false, true);
}catch(e){}
}
When I read the source code of Huanyu’s dreamplayer player today, I found that Huanyu Yu also repaired IE's background cache, but he didn't consider that this phenomenon no longer exists in IE7. This is a relevant code in evml.js~ (By the way, he muttered a few words: This guy never writes JS. Adding semicolons was like this before, and it is still like this now. How can we compress it like this? Ha~ The following code has been added with semicolons according to my habit, even if it is only two or three sentences~)
Program code
window.isIE=navigator.appName.indexOf( "Microsoft")==0;
if(isIE){
document.documentElement.addBehavior("#default#userdata");
document.execCommand("BackgroundImageCache",false,true);
}
A while back a lot of people where covering how to work around the bug that IE always
reloads background images from the server, leading to your UI flickering.
Dean wrote one and lots of others wrote the same thing. Today, I saw this simple workaround
(from a fellow Googler who worked at Microsoft before):
document.execCommand("BackgroundImageCache", false, true )
Much simpler but makes me wonder why this is not the default setting?
/**
* Related replies
* by Nicholas C. Zakas @2007-02-26
*/
I've actually wondered about this "bug" for a while.
I'm sure somewhere along the line this decision was made for a logical reason…
maybe they didn't anticipate how much background images would be used, or maybe they thought
there was some use case under which it would be desirable not to cache the background image.
I'm generally not big on overriding things that seem to be design decisions (which this seems to be).
I've never really thought this was a "bug"…bugs don't usually have switches that say "turn off bug".

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Dreamweaver CS6
Visual web development tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.