An explanation of error function parameters in Ajax

The status in the Xhr.status and error functions is different, and the status in the error function mainly includes: "Success", "Notmodified", "Error", "Timeout", "ParserError", and xhr.status the following.

I. Error:function (XMLHttpRequest, Textstatus, Errorthrown)
{
}
(Default: Automatically determine (XML or HTML) the call time when a request fails. The parameters have the following three: XMLHttpRequest object, error message, and (optionally) the error object being captured. If an error occurs, the error message (the second argument) may also be "timeout", "error", "Notmodified", and "ParserError", in addition to being null.

Textstatus:

"Timeout", "error", "Notmodified" and "ParserError".

Second, the first parameter returned by the error event XMLHttpRequest has some useful information:

Xmlhttprequest.readystate:

Status code

0-(uninitialized) has not yet called the Send () method

1-(load) called the Send () method, the request is being sent, the server connection has been established

2-(loading complete) the Send () method executes, has received the full response content, the request has been received

3-(interactive) parsing of response content, request processing

4-(complete) Response content resolution completed, can be called on the client, request completed, and response ready

Third, data: "{}", the data is empty also must pass "{}"; otherwise the return is in XML format. and prompt ParserError.

There is also a relationship between the ParserError and header types. and coded header (' content-type:text/html; Charset=utf8 ');

Five, Xmlhttprequest.status:

0XX: Status not initialized
1xx-Information Tips
These status codes represent a temporary response. The client should be prepared to receive one or more 1xx responses before receiving a regular response.
100-Continue.
101-Switch protocol.
2xx-success
This type of status code indicates that the server successfully accepted the client request.
200-OK. The client request was successful.
201-created.
202-accepted.
203-Non-authoritative information.
204-no content.
205-Reset the content.
206-Partial content.
3xx-redirection
The client browser must take more action to implement the request. For example, the browser might have to request a different page on the server, or repeat the request through a proxy server.
301-The object has been permanently moved, that is, permanent redirection.
302-The object has been temporarily moved.
304-not modified.
307-Temporary redirection.
4xx-Client Error
An error occurred and the client appears to be having problems. For example, a client requests a page that does not exist, and the client does not provide valid authentication information. 400-Bad request.
401-access is denied. IIS defines a number of different 401 errors, which indicate a more specific cause of the error. These specific error codes are displayed in the browser, but are not displayed in the IIS log:
401.1-Login failed.
401.2-server configuration caused logon failure.
401.3-not authorized due to ACL restrictions on resources.
401.4-Filter Authorization failed.
401.5-ISAPI/CGI application authorization failed.
401.7– access is denied by the URL authorization policy on the Web server. This error code is dedicated to IIS6.0.
403-Forbidden: IIS defines a number of different 403 errors that indicate a more specific cause of the error:
403.1-execution access is forbidden.
403.2-Read access is forbidden.
403.3-Write access is forbidden.
403.4-Requires SSL.
403.5-Requires SSL128.
The 403.6-IP address is rejected.
403.7-Requires a client certificate.
403.8-site access is denied.
403.9-Excessive number of users.
403.10-Invalid configuration.
403.11-Password change.
403.12-Deny access to the mapping table.
403.13-The client certificate is revoked.
403.14-Reject directory list.
403.15-Client access permission exceeded.
403.16-Client certificate is not trusted or invalid.
403.17-The client certificate has expired or is not yet valid.
403.18-The requested URL cannot be executed in the current application pool. This error code is dedicated to IIS6.0.
403.19-CGI cannot be executed for clients in this application pool. This error code is dedicated to IIS6.0.
403.20-passport Login failed. This error code is dedicated to IIS6.0.
404-not found.
404.0-(None) – No files or directories found.
404.1-Unable to access the Web site on the requested port.
The 404.2-web service extension lockout policy blocks this request.
The 404.3-mime mapping policy blocks this request.
405-The HTTP verb used to access this page is not allowed (method not allowed)
406-The client browser does not accept the MIME type of the requested page.
407-proxy authentication is required.
412-Precondition failed.
413– request entity is too large.
414-The request URI is too long.
415– media types not supported.
The range requested by 416– is not sufficient.
417– execution failed.
423– a locked error.
5xx-Server Error
The server could not complete the request because it encountered an error.
500-Internal server error.
The 500.12-application is busy restarting on the Web server.
The 500.13-web server is too busy.
500.15-Direct Request Global.asa is not allowed.
500.16–unc authorization credentials are incorrect. This error code is dedicated to IIS6.0.
The 500.18–url authorization store cannot be opened. This error code is dedicated to IIS6.0.
500.100-Internal ASP error.
501-The header value specifies the configuration that is not implemented.
An invalid response was received when the 502-web server was used as a gateway or proxy server.
The 502.1-cgi application timed out.
502.2-CGI Application error. Application.
503-The service is not available. This error code is dedicated to IIS6.0.
The 504-gateway timed out.
505-http version is not supported.
Ftp
1xx-a definite initial reply
These status codes indicate that an operation has started successfully, but the client wants to get another reply before continuing with the new command.
110 Restart Tag reply.
120 service is ready, starting in nnn minutes.
125 The data connection is open and the transfer is starting.
150 file status OK, ready to open data connection.
2xx-sure to complete the reply
An operation has been successfully completed. The client can execute the new command. 200 command OK.
202 commands are not executed and there are too many commands on the site.
211 System Status, or system help reply.
212 Directory status.
213 file status.
214 Help message.
215NAME system type, where name is the official system name listed in the Assignednumbers document.
220 The service is ready to execute the request of the new user.
221 Service closes the control connection. If appropriate, please log out.
225 Data connection Open, no in-progress transfer.
226 Close the data connection. The requested file operation was successful (for example, transferring a file or discarding a file).
227 Enter passive mode (H1,H2,H3,H4,P1,P2).
230 The user is logged in and continues.
250 The requested file operation is correct and completed.
257 "PATHNAME" has been created.
3xx-affirmative in the middle reply
The command was successful, but the server needs more information from the client to complete the processing of the request. 331 user name is correct, password required.
332 You need to log in to your account.
350 The requested file operation is waiting for further information.
4xx-Transient negation Completion reply
The command is unsuccessful, but the error is temporary. If the client retries the command, it may execute successfully. 421 service is not available and the control connection is shutting down. If the service determines that it must be closed, this response is sent to any command.
425 The data connection cannot be opened.
426connectionclosed;transferaborted.
450 The requested file operation was not performed. The file is not available (for example, the file is busy).
451 requested operation aborted: Local error is being processed.
452 the requested operation was not performed. The system does not have enough storage space.
5xx-permanent negation of complete reply
The command is unsuccessful and the error is permanent. If the client retries the command, the same error will occur again. 500 syntax error, command not recognized. This may include errors such as the command line being too long.
501 There are syntax errors in the arguments.
502 command not executed.
503 wrong sequence of commands.
504 command not executed for this parameter.
530 not logged in.
532 The account is required to store the file.
550 the requested operation was not performed. The file is not available (for example, the file was not found and no access was granted).
551 requested operation aborted: unknown page type.
552 requested file operation terminated abnormally: storage allocation exceeded (for current directory or dataset).
553 The requested operation was not performed. The file name is not allowed.
Common FTP status codes and their causes
The 150-FTP uses two ports: 21 for sending commands, and 20 for sending data. Status code 150 indicates that the server is ready to open a new connection on port 20 and send some data.
226-The command opens a data connection on port 20 to perform operations, such as transferring files. The operation completed successfully and the data connection is closed.
230-The status code is displayed after the client sends the correct password. It indicates that the user has successfully logged on.
331-The status code is displayed after the client sends the user name. The status code is displayed regardless of whether the provided user name is a valid account in the system.
426-The command opens the data connection to perform the operation, but the operation has been canceled and the data connection is closed.
530-The status code indicates that the user cannot log on because the user name and password combination is not valid. If you are logged on with a user account, you might type an incorrect user name or password, or you may choose to allow only anonymous access. If you log on with an anonymous account, the configuration of IIS may deny anonymous access.
550-The command was not executed because the specified file is not available. For example, the file you want to get does not exist, or you try to put the file into a directory where you do not have write permission.

12029: Network does not pass

An explanation of error function parameters in Ajax