javascript中相对路径和绝对路径的区别

Question

Have small clarifications,

As of my knowledge these are the relative and absolute paths,

Completely relative: <img src="kitten.png"/>   
Absolute in all respects: <img src="http://www.foo.com/images/kitten.png">

What is the difference between Relative path and absolute path?

Is there any performance issues occur for using these paths?

Will we get any secure for the sites ?

Is there any way of converting absolute path to relative

Answer 1

The path with reference to root directory is called absolute . The path with reference to current directory is called relative .

Answer 2

What is the difference between Relative path and absolute path?

One has to be calculated with respect to another URI. The other does not.

Is there any performance issues occures for using these paths?

Nothing significant.

We will get any secure for the sites ?

No

Is there any way to converting absolute path to relative

In really simplified terms: Working from left to right, try to match the scheme, hostname, then path segments with the URI you are trying to be relative to. Stop when you have a match.

Answer 3

Completely relative:

<img src="kitten.png"/>

this is a relative path indeed.

Absolute in all respects:

<img src="http://www.foo.com/images/kitten.png"/>

this is a URL, and it can be seen in some way as an absolute path, but it's not representative for this matter.

The difference between relative and absolute paths is that when using relative paths you take as reference the current working directory while with absolute paths you refer to a certain, well known directory. Relative paths are useful when you make some program that has to use resources from certain folders that can be opened using the working directory as a starting point.

Example of relative paths:

• image.png , which is the equivalent to .\\image.png (in Windows) or ./image.png (anywhere else). The . explicitly specifies that you're expressing a path relative to the current working directory, but this is implied whenever the path doesn't begin at a root directory (designated with a slash), so you don't have to use it necessarily (except in certain contexts where a default directory (or a list of directories to search) will be applied unless you explicitly specify some directory).

• ..\\images\\image2.jpg This way you can access resources from directories one step up the folders tree. The ..\\ means you've exited the current folder, entering the directory that contains both the working and images folders. Again, use \\ in Windows and / anywhere else.

Example of absolute paths:

• D:\\documents\\something.doc
• E:\\music\\good_music.mp3

and so on.

Answer 4

Imagine you have a window open on http://www.foo.com/bar/page.html In all of them (HTML, Javascript and CSS):

opened_url = http://www.foo.com/bar/page.html
base_path = http://www.foo.com/bar/
home_path = http://www.foo.com/
/kitten.png = Home_path/kitten.png
kitten.png = Base_path/kitten.png

In HTML and Javascript, the base_path is based on the opened window. In big javascript projects you need a BASEPATH or root variable to store the base_path occasionally. (like this )

In CSS the opened url is the address of which your .css is stored or loaded, its not the same like javascript with current opened window in this case.

And for being more secure in absolute paths it is recommended to use // instead of http:// for possible future migrations to https:// . In your own example, use it this way:

<img src="//www.foo.com/images/kitten.png">

Answer 5

Relative Paths

A relative path assumes that the file is on the current server. Using relative paths allows you to construct your site offline and fully test it before uploading it.

For example:

php/webct/itr/index.php

.

Absolute Paths

An absolute path refers to a file on the Internet using its full URL. Absolute paths tell the browser precisely where to go.

For example:

http://www.uvsc.edu/disted/php/webct/itr/index.php

Absolute paths are easier to use and understand. However, it is not good practice on your own website. For one thing, using relative paths allows you to construct your site offline and fully test it before uploading it. If you were to use absolute paths you would have to change your code before uploading it in order to get it to work. This would also be the case if you ever had to move your site or if you changed domain names.

Reference: http://openhighschoolcourses.org/mod/book/tool/print/index.php?id=12503

Answer 6

如果您使用http://www.foo.com/abc上的相对版本，您的浏览器将查看http://www.foo.com/abc/kitten.png以获取该图像，并且将获得404 - 未找到。

Answer 7

Going Relative:

• You could download a self-contained directory (maybe a zipped file) and open links from an html or xml locally without need to reach the server. This increases speed performance significantly, specially if you have to deal with a slow network.

Going Absolute:

• You would have to swallow the network speed, but in terms of security you could prevent certain users to see certain files or increase network traffic if (and only if...) that is good for you.

Answer 8

I think this example will help you in understanding this more simply.

Path differences in Windows

Windows absolute path C:\\Windows\\calc.exe

Windows non absolute path (relative path) calc.exe

In the above example, the absolute path contains the full path to the file and not just the file as seen in the non absolute path. In this example, if you were in a directory that did not contain "calc.exe" you would get an error message. However, when using an absolute path you can be in any directory and the computer would know where to open the "calc.exe" file.

Path differences in Linux

Linux absolute path /home/users/c/computerhope/public_html/cgi-bin

Linux non absolute path (relative path) /public_html/cgi-bin

In these example, the absolute path contains the full path to the cgi-bin directory on that computer. How to find the absolute path of a file in Linux Since most users do not want to see the full path as their prompt, by default the prompt is relative to their personal directory as shown above. To find the full absolute path of the current directory use the pwd command.

It is a best practice to use relative file paths (if possible).

When using relative file paths, your web pages will not be bound to your current base URL. All links will work on your own computer (localhost) as well as on your current public domain and your future public domains.