http://gd.189.cn/product/biz/qykd/?in_cmpid=zqsy-left-ywbl-qykd
麻省理工出品的图形化编程软件,基于Web,在线使用,有图像、声音、动画等。
1968年,MIT还出品了一款叫做LOGO的语音,也是笔者小学学的计算机语音。这里有在线版:
生成秘钥对(如果已经有就不用再生成了):
a@A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A
今天下载Google的一张图,截了里面约1/100的面积,另存为PNG,结果尺寸为40K,比原来的整张图还大3倍,惊讶不已。用pngcrush后可压缩到1/10大小。好东西!
http://pmt.sourceforge.net/pngcrush/
手机:
@media only screen and (min-device-width: 480px){ /* css样式 */ }
平板:
@media only screen and (min-device-width: 768px){ /* css样式 */ }
html {
background: url(images/bg.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
这是一个可笑的问题,要花时间解决这么可笑的问题,体现了中美IT效率的差距。
SELECT * FROM
(
SELECT *, MAX(field) AS max_field
FROM mytable
GROUP BY field_id
) t
ORDER BY max_field
其中,field,field_id应替换成具体的列名,mytable替换成具体的表名
display: inline-block;
*display: inline; // 星号表示专用于IE7及以下的浏览器
zoom: 1;
还可以考虑加入引用改CSS的条件(但不是必须)
<!–-[if IE 7]>
<link rel="stylesheet" href="ie7.css" type="text/css" />
<![endif]–->
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