我正在尝试向
提出请求但我正在努力解决他们的问题。完整的错误消息是:
XMLHttpRequest cannot load http://ofmpub.epa.gov/enviro/frs_rest_services.get_facilities?facility_name=scrap&state_abbr=VA&program_output=yes&output=JSON. Response for preflight is invalid (redirect)
这是我的代码的样子。我以为我用*设置了正确的标题,但我猜不是。这里有什么问题?
fetchData (url) {
var that = this;
return new Promise(function(resolve, reject) {
var req = new XMLHttpRequest();
req.open('GET', url, true);
req.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
req.setRequestHeader('Access-Control-Allow-Origin', '*');
req.setRequestHeader('Access-Control-Allow-Methods', 'GET');
req.onload = function() {
if (req.status == 200) {
console.log(req.responseText);
that.updateData(JSON.parse(req.responseText));
resolve(req);
}
else {
reject(Error(req.statusText));
}
};
// Handle network errors
req.onerror = function() {
reject(Error("Network Error"));
};
// Make the request
req.send();
});
}