查看代码如下所示：
// Callback for when everything is done
// It is defined here because jslint complains if it is declared
// at the end of the function (which would be more logical and readable)
function done( status, nativeStatusText, responses, headers ) {
var isSuccess, success, error, response, modified,
statusText = nativeStatusText;
// Called once
if ( state === 2 ) {
return;
}
// State is "done" now
state = 2;
// Clear timeout if it exists
if ( timeoutTimer ) {
clearTimeout( timeoutTimer );
}
// Dereference transport for early garbage collection
// (no matter how long the jqXHR object will be used)
transport = undefined;
// Cache response headers
responseHeadersString = headers || "";
// Set readyState
jqXHR.readyState = status > 0 ? 4 : 0;
// Get response data
if ( responses ) {
response = ajaxHandleResponses( s, jqXHR, responses );
}
// If successful, handle type chaining
if ( status >= 200 && status < 300 || status === 304 ) {
// Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
if ( s.ifModified ) {
modified = jqXHR.getResponseHeader("Last-Modified");
if ( modified ) {
jQuery.lastModified[ ifModifiedKey ] = modified;
}
modified = jqXHR.getResponseHeader("Etag");
if ( modified ) {
jQuery.etag[ ifModifiedKey ] = modified;
}
}
// If not modified
if ( status === 304 ) {
statusText = "notmodified";
isSuccess = true;
// If we have data
} else {
isSuccess = ajaxConvert( s, response );
statusText = isSuccess.state;
success = isSuccess.data;
error = isSuccess.error;
isSuccess = !error;
}
} else {
// We extract error from statusText
// then normalize statusText and status for non-aborts
error = statusText;
if ( !statusText || status ) {
statusText = "error";
if ( status < 0 ) {
status = 0;
}
}
}
// Set data for the fake xhr object
jqXHR.status = status;
jqXHR.statusText = ( nativeStatusText || statusText ) + "";
// Success/Error
if ( isSuccess ) {
deferred.resolveWith( callbackContext, [ success, statusText, jqXHR ] );
} else {
deferred.rejectWith( callbackContext, [ jqXHR, statusText, error ] );
}
// Status-dependent callbacks
jqXHR.statusCode( statusCode );
statusCode = undefined;
if ( fireGlobals ) {
globalEventContext.trigger( "ajax" + ( isSuccess ? "Success" : "Error" ),
[ jqXHR, s, isSuccess ? success : error ] );
}
// Complete
completeDeferred.fireWith( callbackContext, [ jqXHR, statusText ] );
if ( fireGlobals ) {
globalEventContext.trigger( "ajaxComplete", [ jqXHR, s ] );
// Handle the global AJAX counter
if ( !( --jQuery.active ) ) {
jQuery.event.trigger( "ajaxStop" );
}
}
}