HTML Reference

Quick Reference

When a browser requests a service from a web server, the server returns a code along with the document/asset, like “404 Not Found” or “200 OK”.

1xx: Information

Message:Description:
100 ContinueThe server has received the request headers, and the client should proceed to send the request body
101 Switching ProtocolsThe requester has asked the server to switch protocols
103 Early HintsUsed with the link header to allow the browser to start preloading resources while the server prepares a response

2xx: Successful

Message:Description:
200 OKThe request is OK (this is the standard response for successful HTTP requests)
201 CreatedThe request has been fulfilled and a new resource is created
202 AcceptedThe request has been accepted for processing, but the processing has not been completed
203 Non-Authoritative InformationThe request has been successfully processed, but is returning information that may be from another source
204 No ContentThe request has been successfully processed, but is not returning any content
205 Reset ContentThe request has been successfully processed, but is not returning any content, and requires that the requester reset the document view
206 Partial ContentThe server is delivering only part of the resource due to a range header sent by the client

3xx: Successful

Message:Description:
300 Multiple ChoicesA link list with a max of five addresses; the user can select a link and go to that location
301 Moved PermanentlyThe requested page has permanently moved to a new URL
302 FoundThe requested page has moved temporarily to a new URL
303 See OtherThe requested page can be found under a different URL
304 Not ModifiedIndicates the requested page has not been modified since last requested
307 Temporary RedirectThe requested page has moved temporarily to a new URL
308 Permanent RedirectThe requested page has moved permanently to a new URL

4xx: Successful

Message:Description:
400 Bad RequestThe request cannot be fulfilled due to bad syntax
401 UnauthorizedThe request was a legal request, but the server is refusing to respond to it; for use when authentication is possible but has failed or not yet been provided
402 Payment RequiredReserved for future use
403 ForbiddenThe request was a legal request, but the server is refusing to respond to it
404 Not FoundThe requested page could not be found, but may be available again in the future
405 Method Not AllowedA request was made of a page using a request method not supported by that page
406 Not AcceptableThe server can only generate a response that is not accepted by the client
407 Proxy Authentication RequiredThe client must first authenticate itself with the proxy
408 Request TimeoutThe server timed out waiting for the request
409 ConflictThe request could not be completed because of a conflict in the request
410 GoneThe requested page is no longer available
411 Length RequiredThe "Content-Length" is not defined; the server will not accept the request without it
412 Precondition FailedThe precondition given in the request evaluated to false by the server
413 Request Too LargeThe server will not accept the request because the request entity is too large
414 Request-URI Too LongThe server will not accept the request because the URI is too long; occurs when you convert a POST request to a GET request with a long query string
415 Unsupported Media TypeThe server will not accept the request because the media type is not supported
416 Range Not SatisfiableThe client has asked for a portion of the file, but the server cannot supply that portion
417 Expectation FailedThe server cannot meet the requirements of the expect request-header field

5xx: Successful

Message:Description:
500 Internal Server ErrorA generic error message given when no more specific message is suitable
501 Not ImplementedThe server either does not recognize the request method, or it lacks the ability to fulfill the request
502 Bad GatewayThe server was acting as a gateway or proxy and received an invalid response from the upstream server
503 Service UnavailableThe server is currently unavailable (overloaded or down)
504 Gateway TimeoutThe server was acting as a gateway or proxy and did not receive a timely response from the upstream server
505 HTTP Version Not SupportedThe server does not support the HTTP protocol version used in the request
511 Network Authentication RequiredThe client needs to authenticate to gain network access

HTML Notes:

  • In our HTML section the term “tag” and “element” are often used interchangeably to refer to both the tag used to create a page element and the element created by the tag (<p> tag = <p> element = paragraph on the page)
  • HTML5 is not case sensitive; so <P> is the same as <p>, <H1> is the same as <h1>
  • Global attributes can be used with all HTML tags and are therefore not mentioned on every tag page
  • To write clean, readable HTML code, it is best to use indentation whereas elements within elements are indented (tabbed or spaces) to create something that looks like a project outline
  • The browser will automatically remove any extra spaces and lines in your HTML code when the page is displayed
  • Double quotes or single quotes can be used around HTML attribute values, but when the attribute value itself contains one form of quote, it will be necessary to use the other around the attribute

We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.