```javascript
var xhr = new XMLHttpRequest();
xhr.timeout = 5000;
var requestURL = URL + '/' + apiName;
xhr.open("POST",requestURL, true);
xhr.setRequestHeader("Content-Type","application/json");
// xhr.setResponseType = "json";
xhr.onreadystatechange = function() {
if(xhr.readyState === 4 && xhr.status == 200){
try {
var ret = JSON.parse(xhr.responseText);
if(handler !== null){
if (typeof ret == 'object' && ret.hasOwnProperty("Auth") && ret.hasOwnProperty("randNum") && ret == checkAuth(ret)) {
handler(1,'',ret);
}else{
handler(-2,'请求异常','');
}
}
} catch (e) {
console.log("err:" + e);
handler(-2,'请求异常','');
}
}
};
var pData = new FormData();
pData.append("test","111");
xhr.send(pData);
```