怎么会等于1223
1223又代表什么？郁闷ing......
------解决方案--------------------------------------------------------
1223 is apparently a bug in IE
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// Safari is braindead here: any status code other than 200 is converted to undefined
// IE invents its own 1223 status code
if ( 204 == xmlhttp.status || xmlhttp.status == null || xmlhttp.status == 1223 ) {
if ( null != f )
google中搜的，