1, IE5, 6 Use ActiveX (window. ActiveXObject)
Version: msxml2.xmlhttp.6.0 msxml2.xmlhttp.3.02, other major browsers: built-in constructors (window. XMLHttpRequest) Create objects for all browsers function createxmlhttprequest ()
{
if (window. XMLHttpRequest)
{
var ohttp = new XMLHttpRequest ();
return ohttp;
}
else if (window. ActiveXObject)
{
var versions=["msxml2.xmlhttp.6.0",
"Msxml2.xmlhttp.3.0"
];
for (Var i=0;i < versions.length;i++)
{
try{
var ohttp= new ActiveXObject (Versions[i]);
return ohttp;
}
catch (Error) {
Do nothing here
}
}
}
return null;
} 3, open (requesttype,url,ture/false(Asynchronous/Sync); method initializes the object 4, the way to synchronize the request var ohttp = Createxmlhttprequest ();//Synchronous request
Ohttp.open ("GET", "Http://localhost/myTextFile.txt", false);
Ohttp.send (NULL);
if (Ohttp.status = = 200)
{
Alert ("The text was found!");
}
else if (ohttp.status==404) {
Alert ("The text file could not being found!");
}
else{
alert ("The server returned a Status code of "+ohttp.status"; } 5, Ajax status value 0-(uninitialized) has not yet called Send () Method 1-(load) called Send () method, sending request 2-(load complete) the Send () method executes, has received full response content 3-(interaction) is parsing the response content 4-(completion) Response content resolution completed, can be called on the client 6, HTTP status Code 3-AJAX status code Description 1**: Request received, continue processing 2**: Operation received successfully, analysis, accept 3**: The request must be processed further 4**: The request contains an error syntax or cannot be completed 5**: The server performs a fully valid request failure 100 --The customer must continue to make a request 101--client requests that the server convert the HTTP protocol version 200--transaction success 201--prompt to know the url202--acceptance and processing of the new file, but processing incomplete 203--return information indeterminate or incomplete 204--request received, But the return information is empty 205--the server completes the request, the user agent must reset the currently browsed file 206--the server has completed a partial user's GET request 300--the requested resource can get 301--delete request data in multiple locations 302--found the request data at other addresses 303- -Advise clients to access other URLs or access methods 304--the client has performed a get, but the file has not changed 305--the requested resource must be 306--the code used in the previous version of HTTP from the address specified by the server and is no longer used in the current version 307-- Declare the requested resource temporary delete 400--error request, such as syntax error 401--request authorization failed 402--retain valid Chargeto header response 403--request does not allow 404--no discovery file, query, or url405-- The method defined by the user in the Request-line field does not allow 406--to request the resource to be inaccessible based on the accept drag sent by the user 407--similar to 401, the user must first be authorized on the proxy server 408--the client does not complete the request within the user-specified time of starvation 409-- The request cannot be completed on the current resource state 410--server no longer has this resource and no further reference address411--server rejects a user-defined Content-length property request 412--One or more request header fields in the current request error 413--the requested resource is greater than the server allowed size 414--The requested resource URL is longer than the length allowed by the server 415-- The request resource does not support the request Item format 416--request contains a range request header field that does not have a range indication value within the current request resource scope, and the request does not contain the If-range request header field 417--The server does not meet the expected value specified by the request Expect header field. If it is a proxy server, the next level of server may not meet the request 500--server generates an internal error 501--the server does not support the requested function 502--the server is temporarily unavailable, sometimes to prevent the system overload 503--server overload or pause maintenance 504--Gateway overload, The server responds to the user with another gateway or service, and the wait time setting is longer 505--the server does not support or denies the HTTP version specified in the request header jqurey implement Level 3 linkage------------ http:// Www.cnblogs.com/bestsamcn/p/4804864.html
Native Ajax notation (Ajax status values)
