ajax的status为201依然触发jquery的error事件的问题

 // Determine if successful，判断status的大小
        isSuccess = status >= 200 && status <300 || status === 304;

        // Get response data
        if (responses) {
            respOnse= ajaxHandleResponses(s, jqXHR, responses);
        }

        // Convert no matter what (that way responseXXX fields are always set)，在此处对response的data进行转化。下面附有ajaxConvert的源码。
        respOnse= ajaxConvert(s, response, jqXHR, isSuccess);

        // If successful, handle type chaining
        if (isSuccess) {

            // 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[cacheURL] = modified;
                }
                modified = jqXHR.getResponseHeader("etag");
                if (modified) {
                    jQuery.etag[cacheURL] = modified;
                }
            }

            // if no content
            if (status === 204 || s.type === "HEAD") {
                statusText = "nocontent";

                // if not modified，判断状态是否为304

            } else if (status === 304) {
                statusText = "notmodified";

                // If we have data, let's convert it。
            } else {
                statusText = response.state;
                success = response.data;
                error = response.error;
                isSuccess = !error;
            }
        } else {
            // Extract error from statusText and normalize for non-aborts
            error = statusText;
            if (status || !statusText) {
                statusText = "error";
                if (status <0) {
                    status = 0;
                }
            }
        }

function ajaxConvert( s, response, jqXHR, isSuccess ) {
var conv2, current, conv, tmp, prev,
cOnverters= {},

// Work with a copy of dataTypes in case we need to modify it for conversion
dataTypes = s.dataTypes.slice();

// Create converters map with lowercased keys
if ( dataTypes[ 1 ] ) {
for ( conv in s.converters ) {
converters[ conv.toLowerCase() ] = s.converters[ conv ];
}
}

current = dataTypes.shift();

// Convert to each sequential dataType
while ( current ) {

if ( s.responseFields[ current ] ) {
jqXHR[ s.responseFields[ current ] ] = response;
}

// Apply the dataFilter if provided
if ( !prev && isSuccess && s.dataFilter ) {
respOnse= s.dataFilter( response, s.dataType );
}

prev = current;
current = dataTypes.shift();

if ( current ) {

// There's only work to do if current dataType is non-auto
if ( current === "*" ) {

current = prev;

// Convert response if prev dataType is non-auto and differs from current
} else if ( prev !== "*" && prev !== current ) {

// Seek a direct converter
cOnv= converters[ prev + " " + current ] || converters[ "* " + current ];

// If none found, seek a pair
if ( !conv ) {
for ( conv2 in converters ) {

// If conv2 outputs current
tmp = conv2.split( " " );
if ( tmp[ 1 ] === current ) {

// If prev can be converted to accepted input
cOnv= converters[ prev + " " + tmp[ 0 ] ] ||
converters[ "* " + tmp[ 0 ] ];
if ( conv ) {

// Condense equivalence converters
if ( cOnv=== true ) {
cOnv= converters[ conv2 ];

// Otherwise, insert the intermediate dataType
} else if ( converters[ conv2 ] !== true ) {
current = tmp[ 0 ];
dataTypes.unshift( tmp[ 1 ] );
}
break;
}
}
}
}

// Apply converter (if not an equivalence)
if ( conv !== true ) {

// Unless errors are allowed to bubble, catch and return them
if ( conv && s.throws ) {
respOnse= conv( response );
} else {
try {
respOnse= conv( response );
} catch ( e ) {
return {
state: "parsererror",
error: conv ? e : "No conversion from " + prev + " to " + current
};
}
}
}
}
}
}

return { state: "success", data: response };
}