Jquery请求API，AJax,Post,Get提交,失败，错误的处理

// Assign handlers immediately after making the request,
// and remember the jqxhr object for this request
var jqxhr = $.post("example.php",
function() {
	alert("success");
}).done(function() {
	alert("second success");
}).fail(function() {
	alert("error");
}).always(function() {
	alert("finished");
});

// Perform other work here ...
// Set another completion function for the request above
jqxhr.always(function() {
	alert("second finished");
});