function ajax(params) {
params = params || {};
if (!params.url) {
throw new Error('Necessary parameters are missing.'); //必要参数未填
}
var options = {
url: params.url || '',
type: (params.type || 'GET').toUpperCase(),
timeout: params.timeout || 5000,
async: true,
complete: params.complete || function() {},
error: params.error || function() {},
success: params.success || function() {},
dataType: params.dataType || 'json',
data: params.data || {},
jsonp: 'callback',
jsonpCallback: ('jsonp_' + Math.random()).replace('.', '')
};
var formatParams = function(json) {
var arr = [];
for (var i in json) {
arr.push(encodeURIComponent(i) + '=' + encodeURIComponent(json[i]));
}
return arr.join("&");
};
if (options.dataType == 'jsonp') {
//插入动态脚本及回调函数
var $head = document.getElementsByTagName('head')[0];
var $script = document.createElement('script');
$head.appendChild($script);
window[options.jsonpCallback] = function(json) {
$head.removeChild($script);
window[options.jsonpCallback] = null;
hander && clearTimeout(hander);
options.success(json);
options.complete();
};
//发送请求
options.data[options.jsonp] = options.jsonpCallback;
$script.src = options.url + '?' + formatParams(options.data);
//超时处理
var hander = setTimeout(function() {
$head.removeChild($script);
window[options.jsonpCallback] = null;
options.error();
options.complete();
}, options.timeout);
} else {
//创建xhr对象
var xhr = new(self.XMLHttpRequest || ActiveXObject)("Microsoft.XMLHTTP");
if (!xhr) {
return false;
}
//发送请求
options.data = formatParams(options.data);
if (options.type == 'POST') {
xhr.open(options.type, options.url, options.async);
xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
xhr.send(options.data);
} else {
xhr.open(options.type, options.url + '?' + options.data, options.async);
xhr.send(null);
}
//超时处理
var requestDone = false;
setTimeout(function() {
requestDone = true;
if (xhr.readyState != 4) {
xhr.abort();
}
}, options.timeout);
//状态处理
xhr.onreadystatechange = function() {
if (xhr.readyState == 4 && !requestDone) {
if (xhr.status >= 200 && xhr.status < 300) {
var data = options.dataType == "xml" ? xhr.responseXML : xhr.responseText;
console.log(data)
if (options.dataType == "json") {
try {
data = JSON.parse(data);
} catch (e) {
data = eval（'(' + data + ')');
}
}
options.success(data);
} else {
options.error();
}
options.complete();
}
};
}
}
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