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Fix CORS error without disabling security in chrome

I have a javascript code which loads json data from some json_url using ajax requests I am getting folloowing error when running the html in chrome
Access to XMLHttpRequest at json_url from origin 'http://localhost:8000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
To fix this error I am opening chrome by disabling web security through the following command
google-chrome --disable-web-security --user-data-dir="/tmp/chrome_dev_test"
Is there anyway to fix this error so that I can run html on chrome without disabling web security every time?
front-end code used:
function getJSON(url){
$.ajax({
type:'GET',
url:url,
dataType:'json',
contentType:'application/json',
timeout: 3000,
success:function(data){
//do something with data
}
});
}

You need to enable CORS on your server side. Here's a guide for many servers, use what suits you.
https://enable-cors.org/server.html
Also in your client-side code, when you specify your request add that it's a CORS request. For example:
$.ajax({
url: "http://www.someotherdomain.com",
type: "POST",
crossDomain: true, //<-- this right here
data: JSON.stringify(somejson),
dataType: "json",
success: function (response) {
// ...
},
error: function (xhr, status) {
// ...
}
});

Gogs API jquery access allow origin

I am using the postman rest client on Brackets.
Using that client I can request the Gogs api.
But if I want to request it using jquery I get a:
XMLHttpRequest cannot load http://xxx.xxx.xxx.xxx:3000/api/v1/repos/.../.../issues?token=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access.
This is my js code:
var request = $.ajax({
url: apiUrl+'repos/.../.../issues?token='+token,
method: "GET",
dataType: "json",
crossDomain: true
});
request.done(function( data ) {
resolve('it works', data);
});
request.fail(function( jqXHR, textStatus ) {
reject(jqXHR, textStatus);
});
Any ideas how to solve this problem?
Edit:
At the moment it is only for developement. Therefore I can use this Chrome extension: Allow-Control-Allow-Origin: *

PhoneGap - Sending JSON encoding data error

I am using Phonegap to connect to a server to authenticate a user. The server expects the data to be Json encoded, and I will get the response back from the server.
var serviceURL = "http://appdev/PEPS-CS-Services/";
The serviceURL (APPDEV) is hosted on our network within the office.
var loginData = {
'strUniqueID' : '123',
'UserName' : 'User123',
'Password' : 'Password123'
};
I have checked the login credentials and they are fine. When I try the following:
$.ajax({
type: "POST",
url: serviceURL + "services/AuthenticationServices/authenticateUser",
data: loginData,
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(data) {
alert(data);
},
failure: function(errMsg) {
alert(errMsg);
}
});
I get the Access-Control-Allow-Origin error in my console.
XMLHttpRequest cannot load http://appdev/PEPS-CS-Services/services/AuthenticationServices/authenticateUser.
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'http://localhost' is therefore not allowed access.
I had a look around, and I was suggested to use Jsonp as the dataType in the ajax request, which does give me back the response I was looking for. However, it isn't alerted out as it should be, the console shows the url with the parameters used in the loginData variable, as below
Resource interpreted as Script but transferred with MIME type application/xml:
http://appdev/PEPS-CS-Services/services/AuthenticationServices/authenticateUser?callback=jQuery164017807046906091273_1396515434941&strUniqueID=123&UserName=Mark&Password=Password1&_=1396515434963"
When I open the link in a browser i get the correct response, as below
<ns:authenticateUserResponse xmlns:ns="http://services">
<ns:return>SESSION ID HERE</ns:return>
</ns:authenticateUserResponse>
However, I also get the Uncaught SyntaxError: Unexpected token < error below it.
I have tried to change to data: loginData to data: {'data':$.toJSON(loginData)}, but still the same error.
My questions are the following:
Am I sending the data over correctly? Why does the jQuery164017807046906091273_1396515434941 get added to the URL before the parameters?
And why am I getting the Uncaught SyntaxError too?
Is this because the server is sending back the incorrect format of the data? It is currently sending back XML
Any help would be greatly appreciated, thanks

This is a familiar cross context issue, you are not allowed to request resource from another domain with simple ajax call and expect a result.
Instead, use a jsonp call and regiter a callback function to call when return result:
var success = function(data){
/* parse JSON */
data = $.parseJSON(data);
/* show json parsed data */
alert(data);
};
$.ajax({
url: serviceURL + "services/AuthenticationServices/authenticateUser",
dataType: 'jsonp', //use jsonp data type in order to perform cross domain ajax
crossDomain: true,
data: loginData,
success: success,
error: function(errMsg) {
alert(errMsg);
}
});

using $ajax to perform GET request from tomcat server always fail jQuery

I have backend webService on tomcat server.always when I perform any request (post, get),code enters on error method.
jQuery code is:
var jqxhr = $.ajax(
{
type:"GET",
url:url
success: function() {
alert("success");
},
error: function() {
alert("fail");
}
});
my url is:
http://"192.168.20.220":6060/NostServices/rest/user/resend_activation_email/mailex#blah.com
error message on log is:
XMLHttpRequest cannot load http://"192.168.20.220":8080/NostServices/rest/user/resend_activation_email/dsgg#sdfkmj.com.
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'http://"192.168.20.220":8383' is therefore not allowed access.
web service server is tomcat.
response of this requset can be 1 for success and -1 for mail not valid
and always enter on fail method and when I try to alert response it output [object object]
thanks you for your help

It's a JSONP request so your server side script needs to return data wrapped in callback:
For example
var url = 'http://example.com/req.json?callback=?';
$.ajax({
type: 'GET',
url: url,
async: false,
jsonpCallback: 'jsonCallback',
contentType: "application/json",
dataType: 'jsonp',
success: function(json) {
console.log(json);
},
error: function(e) {
console.log(e.message);
}
});
And on server side:
jsonCallback({});

As your error says your code is failing because of the cross domain error problem. A very detailed answer is found here:
No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '...' is therefore not allowed access
Please put in some effort to google these issues, this is a very common thing your trying and all errors have been encountered before and have been resolved somewhere. People will get very annoyed here if you show no effort to debug it yourself or provide all the required detail such as:
All relevant code
Print out of any variables in the code e.g. URL's
Any error message
A list of things you have tried
On a side note a URL should not have quotes it it. It should not be
http://"192.168.1.1":.........
it should be:
http://192.168.1.1:........

Jquery unable to get the response from WCF REST service

I have developed WCF rest service and deployed it on a link that can be accessed via the browser because its action is "GET".
I want to get that data using jQuery. I tried my best to get WCf get response using jQuery
but in vain. I also tried $.Ajax with 'jsonp' with no luck. Can any one help me?
The url is: http://www.lonestarus.com/AndroidApp/AndroidLocation.svc/RestService/getLatestLocation
You can check that url response by pasting url in browser.

You need to set Access-Control-Allow-Origin to value [*] in your response header.
this blog gives the more details how it can be done in WCF REST service
if you were to do this in Web API you could have just added
Response.Headers.Add("Access-Control-Allow-Origin", "*")
calling the service using a fiddle
$(function() {
$.ajax({
url: "http://www.lonestarus.com/AndroidApp/AndroidLocation.svc/RestService/getLatestLocation",
datatype: 'json',
type : 'get',
success: function(data) {
debugger;
var obj = data;
}
});
})​;​
I got the error
XMLHttpRequest cannot load
http://www.lonestarus.com/AndroidApp/AndroidLocation.svc/RestService/getLatestLocation.
Origin http://fiddle.jshell.net is not allowed by
Access-Control-Allow-Origin.

I can't make a cross domain example to show you but
$('#a').load('http://www.lonestarus.com/AndroidApp/AndroidLocation.svc/RestService/getLatestLocation​​​​​​​​​​​​​​​​​?callback=run');​
would work had those things been set.
Your service needs to either enable JSONP callbacks or set the Access-Control-Allow-Origin header for cross domain requests to work, or you need to run the script from the same domain. Given that your url says AndroidApp I'm thinking you want cross domain.

Sample code below:
$.ajax
(
{
type: 'GET',
url: http://www.lonestarus.com/AndroidApp/AndroidLocation.svc/RestService/getLatestLocation,
cache: false,
async: true,
dataType: 'json',
success: function (response, type, xhr)
{
window.alert(response);
},
error: function (xhr)
{
window.alert('error: ' + xhr.statusText);
}
}
);