摘自wiki：The keywords attribute

Search engines began dropping support for metadata provided by the meta element in 1998, and by the early 2000s, most search engines had veered completely away from reliance on meta elements. In July 2002, AltaVista, one of the last major search engines to still offer support, finally stopped considering them.

No consensus exists whether or not the keywords attribute has any effect on ranking at any of the major search engines today. It is speculated that it does, if the keywords used in the meta can also be found in the page copy itself. With respect to Google, thirty-seven leaders in search engine optimization concluded in April 2007 that the relevance of having your keywords in the meta-attribute keywords is little to none and in September 2009 Matt Cutts of Google announced that they are no longer taking keywords into account whatsoever. However, both these articles suggest that Yahoo! still makes use of the keywords meta tag in some of its rankings. Yahoo! itself claims support for the keywords meta tag in conjunction with other factors for improving search rankings. In Oct 2009 Search Engine Round Table announced that “Yahoo Drops The Meta Keywords Tag Also” but informed us that the announcement made by Yahoo’s Senior Director of Search was incorrect. In the corrected statement Yahoo Senior Director of Search states that “…What changed with Yahoo’s ranking algorithms is that while we still index the meta keyword tag, the ranking importance given to meta keyword tags receives the lowest ranking signal in our system…. it will actually have less effect than introducing those same words in the body of the document, or any other section.

var i=10;
function a() {
    alert(i);
    var i = 2;
    alert(i);
};
a();

挺经典的一道题，结果出得让人不得不觉得奇怪，想知道是虾米回事，内部到底是怎么执行的。

	function Person(){
		this.name;
		this.age;
		this.sex;

		this.getName = function(){
			return this.name;
		}

		this.getSex = function(){
			return this.sex;
		}

		this.getAge = function(){
			return this.age;
		}
	}

	function Girl(){
		this.sex = "female";
		this.isSingle = true;
	}

	Girl.prototype = new Person();
	var jessica = new Girl();
	jessica.name = "Jessica";
	jessica.age = "24";

在面向对象的语言中，使用类来创建一个自定义对象。在JavaScript中一切都可以是对象，用什么办法来创建一个自定义对象？

live()与bind()不同的是一次只能绑定一个事件。

这个方法跟传统的bind很像，区别在于用live来绑定事件会给所有当前以及将来在页面上的元素绑定事件(使用委派的方式)。比如说，如果你给页面上所有的li用live绑定了click事件。那么当在以后增加一个li到这个页面时，对于这个新增加的li，其click事件依然可用。而无需重新给这种新增加的元素绑定事件。

要移除用live绑定的事件，请用die方法

通常，我们碰到flash把div给遮住的问题。想到的解决方案都是：

IE：

	<param name="wmode" value="opaque">

	<embed src="/xx.swf" quality="high" wmode="transparent"></embed>