jquery rewrites ajax and uses the load method to report errors after submitting and judging permissions_jquery

No more nonsense, let me just post the code for you.

jQuery(function ($) {
// 备份jquery的ajax方法 
var _ajax = $.ajax;
// 重写ajax方法，先判断登录在执行success函数 
$.ajax = function (opt) {
var _success = opt && opt.success || function (a, b) { };
var _opt = $.extend(opt, {
success: function (data, textStatus) {
// 如果后台将请求重定向到了登录页，则data里面存放的就是登录页的源码，这里需要找到data是登录页的证据(标记) 
if ((typeof data) == 'string' && data.indexOf('shangjiaAjaxExtend') != -1) {
window.location.href = 'http://' + window.location.host + '/S/BusiLogin/Index';
return;
} else {
_success(data, textStatus);
}
}
});
return _ajax(_opt);
};
});

The rewriting principle is: since the closure function is loaded before the script on the page, the $.ajax method can be directly rewritten here.

The key point is that the content in the red part must be retrun, otherwise an error "Uncaught TypeError: Cannot call method 'done' of undefined." will be reported when using the load method to load the page.