A Universal Resource Locator (URL) is a reference or address used to access resources on the internet. It provides a means to locate a specific resource—such as a webpage, image, or video—by specifying the protocol used to retrieve it and the resource's location on the network.
A typical URL consists of several components:
-
Protocol: This indicates the method used to access the resource, such as HTTP (Hypertext Transfer Protocol), HTTPS (secure version of HTTP), FTP (File Transfer Protocol), etc. It is followed by "://".
-
Domain Name or IP Address: This is the address of the server that hosts the resource. It can be a human-readable domain name (like www.example.com) or an IP address (like 192.0.2.1).
-
Port Number (optional): This specifies the port on the server through which the resource can be accessed. If omitted, the default port for the specified protocol is used (e.g., port 80 for HTTP and port 443 for HTTPS).
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Path: This indicates the specific location of the resource on the server. It may represent directories and file names (e.g., /folder/page.html).
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Query String (optional): This is used to pass additional parameters to the server, often in the form of key-value pairs (e.g., ?key1=value1&key2=value2).
-
Fragment Identifier (optional): This points to a specific section within the resource (e.g., #section1).
For example, in the URL https://www.example.com:443/folder/page.html?user=123#section1, the components are as follows:
- Protocol:
https - Domain:
www.example.com - Port:
443 - Path:
/folder/page.html - Query String:
?user=123 - Fragment:
#section1
URLs are essential for navigating the web, enabling users and applications to retrieve information efficiently.