关闭firefox工具条的提示

在拖动某个网页保存为书签时，firefox总是会在工具条上提示:
Drag and drop this icon to create a link to this page
这个很影响操作，可以通过firefox的about:config进行设置:
1. 在地址栏输入: about:config 回车
2. 输入tips，找到browser.chrome.toolbar_tips，修改值为false即可。

wget 使用技巧

wget 是一个命令行的下载工具。对于我们这些 Linux 用户来说，几乎每天都在使用它。下面为大家介绍几个有用的 wget 小技巧，可以让你更加高效而灵活的使用 wget。

1. $ wget -r -np -nd http://example.com/packages/

这条命令可以下载 http://example.com 网站上 packages 目录中的所有文件。其中，-np 的作用是不遍历父目录，-nd 表示不在本机重新创建目录结构。
2. $ wget -r -np -nd --accept=iso http://example.com/centos-5/i386/

与上一条命令相似，但多加了一个 --accept=iso 选项，这指示 wget 仅下载 i386 目录中所有扩展名为 iso 的文件。你也可以指定多个扩展名，只需用逗号分隔即可。
3. $ wget -i filename.txt

此命令常用于批量下载的情形，把所有需要下载文件的地址放到 filename.txt 中，然后 wget 就会自动为你下载所有文件了。
4. $ wget -c http://example.com/really-big-file.iso

这里所指定的 -c 选项的作用为断点续传。
5. $ wget -m -k (-H) http://www.example.com/

该命令可用来镜像一个网站，wget 将对链接进行转换。如果网站中的图像是放在另外的站点，那么可以使用 -H 选项。

原文网址：http://linuxtoy.org/archives/wget-tips.html(2007-10-14 Toy)

Javascript tips of functions usage

These tips are suggested as good programming practices and should lead to easier-to-maintain code.
Define All Functions for a Script First The reason for this tip should be obvious: we need to make sure a function is defined and read by a browser before we can invoke it. Secondarily, if we define all the functions that our code will use in one place, it makes functions easier to find.
Name Functions Well When naming functions and variables, you need to be a little careful. Because functions and variables share the same namespace, you shouldn’t be declaring variables and functions with the same name. It might be a good idea to precede function names with “func” or some other string or letter of your own choosing. So, using such a scheme, if we had a variable named hello and wanted to define a function also called hello, we would use funcHello.
Note
Some developers prefer different casing to distinguish between variables and functions, but this may not be obvious enough. The choice is a matter of style and we leave it open for readers to decide for themselves.
Besides the obvious collision of names, very subtle bugs may slip in when we have similar names, particularly when you consider that functions are created when the document is parsed, while variables are created when the script is run. Notice in the following script how there is a variable as well as a function called x.
var x = 5;
function x()
{
alert("I'm a function!");
}
alert(typeof x);

You might expect the alert to show x to be a function or, more appropriately, an object because it appears to be defined second. However, as you can see here, it is a number.
The output makes sense if you consider when the function and variables are actually created. The function is created as the script is parsed, while the variable gets created as the script runs. While this was a contrived example, it illustrates the importance of understanding how things are created in JavaScript.
Consider Using Linked .js Files for Functions, But Be Cautious While many JavaScript programmers like to put functions in external files, we need to make sure that a function is available before calling it. For example, if we have two .js files (lib1.js and lib2.js), each of which calls functions found in the other, we may have to check to make sure the function is available before calling it because the browser might finish loading one script before the other. In the main document, we would define variables showing the files being loaded as false:
var lib1Loaded = false;
var lib2Loaded = false;

Then, in each of the loaded documents the last line would set the corresponding variables to true. Using this scheme, we would then make sure to look at the value of the variables lib1Loaded or lib2Loaded before any functions that are contained in the files are called. For example:
if (lib1Loaded)
doSomething(x,y,z)

Most of the time such efforts aren’t required, but JavaScript designers should be careful to consider the load order of documents and what happens if certain parts of a script are invoked before an entire document has loaded.
Use Explicit Return Statements Even if your function will not return any values, insert a return statement anyway. JavaScript being an interpreted language, keeping the interpreter from having to do any extra work or make any assumptions should produce better running scripts.
Write Stand-Alone Functions As always, you should practice modular design and pass data into and out from functions using only function arguments, the return statement, and data values that are passed by reference. We should avoid side-effects such as changing global values from within functions. Local variables should always be used to perform calculations that are unique to a function, and hidden functions can be used in the same manner to create special-purpose functions that are not needed anywhere else. The value of going through the trouble to create stand-alone functions in this fashion is that such functions can be reused without worry in a variety of situations.