javascript文档中心

使用javascript创建Microsoft XML DOM,就可以完成这一工作.
// 装入数据.
var source = new ActiveXObject("Microsoft.XMLDOM");
source.async = false
source.load("history.xml");
// 装入样式表.
var stylesheet = new ActiveXObject("Microsoft.XMLDOM");
stylesheet.async = false
stylesheet.load("history.xsl");
使用new ActiveXObject("Microsoft.XMLDOM")创建一个Microsoft XML DOM, 注意async的属性一定要设为false,否则会因为不同步而产生错误.
// 将结果转化为一个DOM文档.
divContent.innerHTML = source.transformNode(stylesheet);
divContent可以定义为<div id="divContent"></div>.
......

AJAX (异步 JavaScript 和 XML) 是个新产生的术语,专为描述JavaScript的两项强大性能.这两项性
能在多年来一直被网络开发者所忽略,直到最近Gmail, Google suggest和google Maps的横空出世才使人
们开始意识到其重要性.
这两项被忽视的性能是:
* 无需重新装载整个页面便能向服务器发送请求.
* 对XML文档的解析和处理．
步骤 1 – "请!" --- 如何发送一个HTTP请求
为了用JavaScript向服务器发送一个HTTP请求, 需要一个具备这种功能的类实例.
这样的类首先由Internet Explorer以ActiveX对象引入, 被称为XMLHTTP. 后来Mozilla, Safari 和其他
浏览器纷纷仿效, 提供了XMLHttpRequest类,它支持微软的ActiveX对象所提供的方法和属性.
因此, 为了创建一个跨浏览器的这样的类实例(对象), 可以应用如下代码:
if (window.XMLHttpRequest) { // Mozilla, Safari, ...
http_request = new XMLHttpRequest();
} else if (window.ActiveXObject) { // IE
http_request = new ActiveXObject("Microsoft.XMLHTTP");
}
(上例对代码做了一定简化,这是为了解释如何创建XMLHTTP类实例.
实际的代码实例可参阅本篇步骤3.)
如果服务器的响应没有XML mime-type header,某些Moz ......

Repaints and Reflows 重绘和重排版
    Once the browser has downloaded all the components of a page—HTML markup, JavaScript, CSS, images—it parses through the files and creates two internal data structures:
    当浏览器下载完所有页面HTML标记，JavaScript，CSS，图片之后，它解析文件并创建两个内部数据结构：
A DOM tree
    A representation of the page structure
一棵DOM树
    表示页面结构
A render tree
    A representation of how the DOM nodes will be displayed
一棵渲染树
    表示DOM节点如何显示
    The render tree has at least one node for every node of the DOM tree that needs to be displayed (hidden DOM elements don't have a corresponding node in the render tree). Nodes in the render tree are called frames or boxes in accordance with the CSS model that treats page elements as boxes with padding, margins, borders, and position. Once the DOM and the render tree ......

第四章 Algorithms and Flow Control 算法和流程控制
    The overall structure of your code is one of the main determinants as to how fast it will execute. Having a very small amount of code doesn't necessarily mean that it will run quickly, and having a large amount of code doesn't necessarily mean that it will run slowly. A lot of the performance impact is directly related to how the code has been organized and how you're attempting to solve a given problem.
    代码整体结构是执行速度的决定因素之一。代码量少不一定运行速度快，代码量多也不一定运行速度慢。性能损失与代码组织方式和具体问题解决办法直接相关。
    The techniques in this chapter aren't necessarily unique to JavaScript and are often taught as performance optimizations for other languages. There are some deviations from advice given for other languages, though, as there are many more JavaScript engines to deal with and their quirks need to be considered, but all of the te ......

Conditionals 条件表达式
    Similar in nature to loops, conditionals determine how execution flows through JavaScript. The traditional argument of whether to use if-else statements or a switch statement applies to JavaScript just as it does to other languages. Since different browsers have implemented different flow control optimizations, it is not always clear which technique to use.
    与循环相似，条件表达式决定JavaScript运行流的走向。其他语言使用if-else或者switch表达式的传统观点也适用于JavaScript。由于不同的浏览器针对流程控制进行了不同的优化，使用哪种技术并不总是很清楚。
if-else Versus switch if-else与switch比较
    The prevailing theory on using if-else versus switch is based on the number of conditions being tested: the larger the number of conditions, the more inclined you are to use a switch instead of if-else. This typically comes down to which code is easier to read. The argument is that if-else is easier to read wh ......

javascript动态装入XML数据

javascript动态装入XML数据

AJAX (异步 JavaScript 和 XML)

AJAX (异步 JavaScript 和 XML)

AJAX (异步 JavaScript 和 XML)

javascript实现自动求和

[翻译]High Performance JavaScript(011)

[翻译]High Performance JavaScript(012)

[翻译]High Performance JavaScript(013)