Web 跨域请求

$(function() {
	‘use strict‘;

	/**
	 * 交互类
	 * @param {object} param 要提交的数据
	 * @param {Object} [ajaxOpt] ajax配置
	 * @param {boolean} [https=false] 是否使用https协议
	 * @constructor
	 */
	var Sync = function(param, ajaxOpt, https) {
		var protocol = this.protocol = https ? ‘https‘: ‘http‘;

		var ajaxOptDefault = {
			url: protocol + ‘://‘+location.host,
			type: ‘GET‘,
			dataType: ‘jsonp‘,
			timeout: 20000
		};

		param = string2JSON(param) || {};

		this.protocol = protocol;
		this.param = $.extend({}, param, ajaxOpt);
		this.ajaxOpt = $.extend({data: this.param}, ajaxOptDefault);
		this.HOST = protocol + ‘://‘+location.host;
	};

	function string2JSON(str){
		if($.isPlainObject(str)) {
			return str;
		}
		var params = {};
		var str2Arr = str.split(‘&‘);
		$.each(str2Arr, function(i, keyVal) {
			var arr = keyVal.split(‘=‘);
			//去除serialize把空格转成+
			params[arr[0]] = decodeURIComponent(arr[1]).replace(/[\+]+/, ‘‘).replace(/[\+]+/, ‘‘);
		});
		return params;
	}

	$.extend(Sync.prototype, {
		/**
		 * 通过get方式(jsonp)提交
		 * @param {String} [url] 请求链接
		 * @return {Object} promise对象
		 */
		get: function(url) {
			var self = this;
			var send = $.ajax(url, this.ajaxOpt);
			return send.then(this.done, function(statues) {
				return self.fail(statues);
			});
		},
		/**
		 * 通过post方式提交，依赖psp_jump.html文件
		 * @param {String} [url] 请求链接
		 * @return {Object} promise对象
		 */
		post: function(url) {
			var deferred = $.Deferred();
			var timer = null;
			var guid = parseInt(new Date().getTime().toString().substr(4), 10);
			var funName =  ‘QBXJsonp‘ + guid;
			var formName = ‘QBXForm‘ + guid;
			var iframeName = ‘QBXIframe‘ + guid;

			// iframe 不能使用attr(‘name‘, xxx) 否则在ie7上添加的不是name属性而是submitName
			var iframe = $(‘<iframe name="‘ + iframeName +‘">‘).hide();
			var param = $.extend({}, this.param, {proxy: this.HOST+‘/proxy.html‘, callback: funName});
			var form = buildForm(param, {name: formName, target: iframeName, url: url || this.ajaxOpt.url});

			window[funName] = function (data){
				clearTimeout(timer);
				var value;
				for (var i in data) {
					if (data.hasOwnProperty(i)) {
						value = decodeURIComponent(data[i]);
						if (value.match(/^(\{.*\})|(\[.*\])$/)) {
							value = $.parseJSON(value);
						}
						data[i] = value;
					}
				}
				deferred.resolve(data);
			};

			timer = setTimeout(function(){
				deferred.reject({
					errno: 999999,
					errmsg: ‘网络超时，请稍后重试‘
				});
			}, this.ajaxOpt.timeout);

			// do some clear
			deferred.always(function(data) {
				$(iframe).remove();
				$(form).remove();
				// IE8以下不支持delete window属性
				try {
					delete window[funName];
				} catch (e){
					window[funName] = null;
				}
			});
			$(document.body).append(iframe).append(form);
			$(form).submit();
			return deferred.then(this.done);
		},
		/**
		 * 收到响应时默认回调
		 * @param {Object} data 数据
		 * @return {Object}
		 */
		done: function (data) {
			var deferred = $.Deferred();
			if (data.errno == 0) {
				deferred.resolve(data);
			} else {
				deferred.reject(data);
			}
			return deferred.promise();
		},
		/**
		 * 未收到响应时默认回调
		 * @param {Object} error 错误信息
		 * @return {Object}
		 */
		fail: function(error) {
			var deferred = $.Deferred();
			deferred.reject({
				errno: 999999,
				errmsg: ‘网络超时，请稍后重试‘
			});
			return deferred.promise();
		}
	});

	/**
	 * 把数据对象转成form元素
	 * @param {Object} data json数据
	 * @param {Object} opts form所需参数或其他数据
	 * @return {Object}
	 */
	function buildForm(data, opts) {
		if (opts.url) {
			opts.action = opts.url;
			delete opts.url;
		}
		opts.method = ‘post‘;
		var $form = $(‘<form>‘).attr(opts).hide();
		$.each(data, function (name, value) {
			$(‘<input>‘).attr({type: ‘hidden‘, name: name, value: value}).appendTo($form);
		});
		return $form[0];
	}
	
	window.Sync = Sync;

});
这样我们就可以通过一下方式进行使用：
var login = function(data) {
	var sync = new Sync(data);
	return sync.post(sync.HOST+‘/login‘);
}
 
login({username: ‘blackMao‘, password: ‘blackMao‘})
	.done(function() {
		alert(‘登陆成功！‘);
	})
	.fail(function(error) {
		alert(error.errmsg);
	});