谷歌的ie9.js ie8.js ie7.js 解决IE5、IE6、IE7、IE8与W3C标准的冲突
http://code.google.com/p/ie7-js/
如果分别用IE5、IE6、IE7浏览同一个网页，将可能出现不一样的效果。
这是它们之间对CSS的解析选择器不一样或错误和个别bug所导致。为了解决这些错误和bug。
我们不得不找到一个能平衡于它们之间的解决方法。
如png透明问题在IE5、IE6下无法显示出其效果，我们可能会使用CSS hack或者引入外部JavaScript来实现。譬如前面我提到过用pngfix的那个方法就是调用外部JavaScript来解决在IE5、IE6下png透明问题。当然还有更多的方法。
而现在有种更加完美的方法能兼容IE5、IE6、IE7的CSS选择器解析不一样问题。那就是： ie7 – js
ie7 – js中是一个JavaScript库（解决IE与W3C标准的冲突的JS库），使微软的Internet Explorer的行为像一个Web标准兼容的浏览器，支持更多的W3C标准，支持CSS2、CSS3选择器。它修复了许多的HTML和CSS问题，并使得透明PNG在IE5、IE6下正确显示。
目前该ie7 – js版本： 2.0 beta 3
用法：
直接引用Google Code服务器上的js文件。
<!--[if lt IE 7]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE7.js">IE7_PNG_SUFFIX=".png";</script>
<![endif]-->
<!--[if lt IE 8]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE8.js">IE7_PNG_SUFFIX=".png";</script>
<![endif]-->
<!--[if lt IE 9]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE9.js">IE7_PNG_SUFFIX=".png";</script>
<![endif]-->
IE7.js
使IE5、IE6升级至兼容IE7
注释使Internet Explorer版本号低于IE7的IE浏览器载入该代码。
<!–[if lt IE 7]>
<script src=”http://ie7-js.googlecode.com/svn/version/2.0(beta3)/IE7.js” type=”text/javascript”></script>
<![endif]–>
IE8.js
使IE5、IE6、IE7支持更多的W3C标准（修复了许多的HTML和CSS问题）。
注释使Internet Explorer版本号小于8的IE浏览器载入该代码，而其它符合标准的浏览器则会忽略该代码，并在IE8出来后不干扰其工作。
<!–[if lt IE 8]>
<script src=”http://ie7-js.googlecode.com/svn/version/2.0(beta3)/IE8.js” type=”text/javascript”></script>
<![endif]–>
让png透明的语句.
<script src="IE8.js">IE7_PNG_SUFFIX=".png";</script>
E7.js is a JavaScript library to make Microsoft Internet Explorer behave like a standards-compliant browser. It fixes many HTML and CSS issues and makes transparent PNG work correctly under IE5 and IE6.
Status
Current version: 2.1 beta4.
Usage
IE7.js
Upgrade MSIE5.5-6 to be compatible with MSIE7.
<!--[if lt IE 7]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE7.js"></script>
<![endif]-->
IE8.js
Upgrade MSIE5.5-7 to be compatible with MSIE8.
<!--[if lt IE 8]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE8.js"></script>
<![endif]-->
You do not need to include IE7.js if you are using IE8.js
IE9.js
Upgrade MSIE5.5-8 to be compatible with modern browsers.
<!--[if lt IE 9]>
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE9.js"></script>
<![endif]-->
You do not need to include IE7/IE8.js if you are using IE9.js
PNG
The script only fixes images named: *-trans.png
If you want the fix to apply to all PNG images then set a global variable as follows:
var IE7_PNG_SUFFIX = ".png";
You must set this variable before including the IE7.js script. Alternatively, you can set the variable inside the IE7.js script element:
<script src="IE8.js">IE7_PNG_SUFFIX=".png";</script>
The suffix will ignore query string parameters. For more fine-grained control you can also set IE7_PNG_SUFFIX to a RegExp object. If you want to use an alternative PNG solution then set the suffix to something that cannot possibly match:
var IE7_PNG_SUFFIX = ":";
By default, the PNG will be stretched (this simulates tiling). If you want to turn this off then set the no-repeat property as follows:
div.example {
background: url(my-trans.png) no-repeat;
}
Unfortunately, the transparent background image cannot be tiled (repeated) using background-repeat. Nor can it be positioned using background-position.
Download
You may link directly to these files if you wish:
http://ie7-js.googlecode.com/svn/version/
Or go to the downloads section to download the current version.
Getting Started
Here is a nice introduction: