Web browsers request pages from web servers by using a URL.

When you click on a link in an HTML page, an underlying <a> tag points to an address on the world wide web.

A Uniform Resource Locator (URL) is used to address a document (or other data) on the world wide web.

A web address, like this: http://www.w3schools.com/html/default.asp follows these syntax rules:

Explanation:

• scheme - defines the type of Internet service. The most common type is http
• host - defines the domain host (the default host for http is www)
• domain - defines the Internet domain name, like w3schools.com
• port - defines the port number at the host (the default port number for http is 80) 
• path - defines a path at the server (If omitted, the document must be stored at the root directory of the web site)
• filename - defines the name of a document/resource

Common URL Schemes

The table below lists some common schemes:

URL Encoding

URLs can only be sent over the Internet using the ASCII character-set.

Since URLs often contain characters outside the ASCII set, the URL has to be converted into a valid ASCII format.

URL encoding converts characters into a format that can be transmitted over the Internet.

URL encoding replaces non ASCII characters with a "%" followed by two hexadecimal digits.

URLs cannot contain spaces. URL encoding normally replaces a space with a + sign.

Try It Yourself

If you click the "Submit" button below, the browser will URL encode the input before it is sent to the server. A page at the server will display the received input.