URL- UNIFORM RESOURCE LOCATOR

UNIFORM RESOURCE LOCATOR

( URL )

URL or Uniform resource locator is the method by which a document or data is addressed in the  World Wide Web. The URL contains the following information:

1. The internal name of the site containing the resources (document data)
2. The type of service the resource is served by (HTTP , FTP etc.)
3. The internet port  number of the service  (if this is omitted, the browser assumes a commonly accepted default value )
4. The location of the resource in the directory structure of server.

Structure of URL :

The following is an outline of the most common from of a URL:

                http://www.computeradda12.blogspot.com:1234/path/subdir/file.html

                       | Service | - host - | port | file and resource details |

Service:   

The first part of the URL is the service specifier ( here HTTP service ) which specifies the access method specifically.  this is the part before the colon.

Address and Port Number :

The second part is usually the internet address of the server , indicated by the double forward slash (//). This address can also contain the optional port number the service list at. The full name is specified by a string like //www.computeradda12.blogspot.com:1234/, Where :1234 means port number 1234. If you want to use the default port number , you can leave out both the colon and the number , i.e // www.computeradda12.blogspot.com/.

Resource Location :

The forward slash after the host and port specifications indicates the end of the address and the beginning of the specification for the file / resource to be accessed. The resource is specified by a path relative to the root directory of the server. 

Absolute URL :

A fully qualified URL that specifies the location of a resource that resides on the internet is called an ABSOLUTE URL.

Relative URL :

A partially qualified URL is the one that specifies a resources on the internet whose location is relative to starting point specified by an Absolute URL . In fact, the concatenated Absolute and  Relative URL's constitute a complete URL. 

Once you have a viewed a document located somewhere on the network ( say, the document https://www.computeradda12.blogspt.com/defalut/.html ) you can use a partial or relative URL to point to another file in the some directory , on the some machine, being served by the same server software. For example , if another file exists in that same directory called 'second html', then second .html is a valid relative URL at that point.

This provide an easy way to build sets of hypertext documents. If a set of hypertext documents are in common directory, they can be referred to ( i.e, by hyperlinks ) by just their files names. however, if a reader is on one of the documents , a jump can be made to any other document in the same directory by just using the other document's filename as the Relative URL at the point. The additional information  ( access method , host name , port number , directory name, etc.)  will be assumed based on the URL used to reach the first document.