首先,我很清楚 jQuery , zepto 等框架的包装并没有问题。所以虽然我做得还挺符合 jQuery 规范的,但其实我做得这个事情并没有实际上的生产意义,只能用于令人更了解实现侧的过程,同时对我个人而言算是一种娱乐…… 对于我做得项目,只有很轻小以致于整个项目代码也到不了 jquery-min.js 文件大小的情况,才会使用我自写的这个发起器,并且不会用源码版,会用压缩版。另外我觉得做一个前后端连用的框架,所有请求都通过 jsonp 的方式,也许反倒可以简洁一些。 ``` var _shaneAjaxRef = { }; /** * @author Shane Loo Li * @version 1.1.0, 2019-7-18 Thursday * @param configObj { } * url * type * data * async * dataType xml, html, script, text will return text itself. json wil return object. jsonp will run return text as JavaScript. * success function * error function * complete function */ var shaneAjax = function(configObj) { if (!configObj || !configObj.url) { return; } try { if (configObj.dataType && configObj.dataType == 'jsonp') { _shaneAjaxRef.goJsonp(configObj); } else { _shaneAjaxRef.goRealAjax(configObj); } } catch (err) { if (configObj.error) { configObj.error(xmlhttp, '' + err, err); } if (configObj.complete) { configObj.complete(xmlhttp, 'error'); } } }; _shaneAjaxRef.buildNewXmlhttp = function() { return window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP"); } _shaneAjaxRef.buildDataStr = function(data) { if (!data) return ''; var result = ''; for (var key in data) { if (data[key] instanceof Array) { var values = data[key]; for (var i = -1; ++i != values.length; ) { if (result) { result += '&'; } result += key + '=' + values[i]; } } else { if (result) { result += '&'; } result += key + '=' + data[key]; } } return result; }; _shaneAjaxRef.goJsonp = function(configObj) { var i = -1; while (++i != 65536 && window['jsonp' + i]) { } window['jsonp' + i] = function(responseDataObj) { if (configObj.success) { configObj.success(responseDataObj, 'success'); } delete window['jsonp' + i]; }; var reqUrl = configObj.url; var dataStr = _shaneAjaxRef.buildDataStr(configObj.data); reqUrl += (reqUrl.indexOf('?') == -1 ? '?' : '&') + 'callback=jsonp' + i; if (dataStr) { reqUrl += '&' + dataStr; } var d_script = document.createElement('script'); d_script.setAttribute('src', reqUrl); document.getElementsByTagName('head')[0].appendChild(d_script); }; _shaneAjaxRef.goRealAjax = function(configObj) { var xmlhttp = _shaneAjaxRef.buildNewXmlhttp(); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4) { var success = xmlhttp.status == 200; if (success) { if (configObj.success) { var dataType = configObj.dataType ? configObj.dataType : 'json'; switch (dataType) { case 'xml': case 'html': case 'script': case 'text': configObj.success(xmlhttp.responseText, 'success'); break; case 'json': configObj.success(JSON.parse(xmlhttp.responseText), 'success'); break; case 'jsonp': configObj.success(eval(xmlhttp.responseText), 'success'); } } } else { if (configObj.error) { configObj.error(xmlhttp, 'http status = ' + xmlhttp.status, null); } } if (configObj.complete) { configObj.complete(xmlhttp, success ? 'success' : 'error'); } } }; var reqMethod = configObj.type ? configObj.type : 'GET'; var reqUrl = configObj.url; var dataStr = _shaneAjaxRef.buildDataStr(configObj.data); if (reqMethod == 'GET' && dataStr) { reqUrl += (reqUrl.indexOf('?') == -1 ? '?' : '&') + dataStr; } var reqAsync = configObj.async === false ? false : true; xmlhttp.open(reqMethod, reqUrl, reqAsync); if (reqMethod == 'POST' || reqMethod == 'PUT') { xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); } if ((reqMethod == 'POST' || reqMethod == 'PUT') && dataStr) { xmlhttp.send(dataStr); } else { xmlhttp.send(); } }; ``` 下面是一个测试程序。如果用 jsonp 就可以访问,否则不行。 ``` var test = function() { console.log(1); // https://www.baidu.com/s?wd=ajax&rsv_spt=1&rsv_iqid=0xf9544c340001dd09&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&rqlang=cn&tn=baiduhome_pg&rsv_enter=1&oq=jQuery%2520ajax&inputT=1899&rsv_t=25bdncCkCLyr12l2gBax5GxF5yjzYUnHj2M%2FMv%2Fd1YsIlJpcW4%2BYljBcIhDw8f9CnkkY&rsv_pq=8e82b6400002164e&rsv_sug3=32&rsv_sug1=20&rsv_sug7=101&rsv_sug2=0&rsv_sug4=2655 shaneAjax({ type: 'GET', url: 'http://www.baidu.com/s', data: { wd: 'ajax', rsv_spt: 1, rsv_iqid: '0xf9544c340001dd09', issp: 1, f: 8, rsv_bp: 1, rsv_idx: 2, ie: 'utf-8', rqlang: 'cn', tn: 'baiduhome_pg', rsv_enter: 1, oq: 'jQuery%20ajax', inputT: 1899, rsv_t: '25bdncCkCLyr12l2gBax5GxF5yjzYUnHj2M/Mv/d1YsIlJpcW4+YljBcIhDw8f9CnkkY', rsv_pq: '8e82b6400002164e', rsv_sug3: 32, rsv_sug1: 20, rsv_sug7: 101, rsv_sug2: 0, rsv_sug4: 2655 }, dataType: 'jsonp', success: function(result) { console.log(result); }, complete: function() { console.log('complete'); } }); console.log(2); }; ```