mui 浏览器跨域实现

from:http://ask.dcloud.net.cn/question/17373

APP开发时 是不需要JSONP支持的 mui本身就支持 但是 如果是微信或者浏览器的普通模式就不支持。所以贴出以下代码 大家可参考使用。（参考了zepto）

var jsonpID = 0;
 $.ajaxJSONP = function(url, options){
if (typeof url === "object") {
 options = url;
 url = undefined;
}
var options = $.extend({}, options || {})
for (var key in $.ajaxSettings) {
if (options[key] === undefined) {
 options[key] = $.ajaxSettings[key];
}
}
 options.url = appendQuery(options.url, '_=' + Date.now())

 options.url = appendQuery(options.url,
 options.jsonp ? (options.jsonp + '=?') : options.jsonp === false ? '' : 'callback=?')
var _callbackName = options.jsonpCallback,
 callbackName = ($.isFunction(_callbackName) ?
 _callbackName() : _callbackName) || ('jsonp' + (++jsonpID)),
 script = document.createElement('script'),
 originalCallback = window[callbackName],
 responseData,
 abort = function(errorType) {
 script.parentNode.removeChild(script)
if (callbackName in window) window[callbackName] = empty
 ajaxComplete('abort', xhr, options)
},
 xhr = { abort: abort }, abortTimeout;
if (options.error) script.onerror = function() {
 xhr.abort()
 options.error()
}

 window[callbackName] = function(data){
 clearTimeout(abortTimeout)
 script.parentNode.removeChild(script)
delete window[callbackName]
 ajaxSuccess(data, xhr, options)
}

 serializeData(options)
 script.src = options.url.replace(/=\?/, '=' + callbackName)
 document.head.appendChild(script)

if (options.timeout > 0) abortTimeout = setTimeout(function(){
 xhr.abort()
 ajaxComplete('timeout', xhr, options)
}, options.timeout) 
return xhr
}