JavaScript jQuery – Fixing CORS Error During AJAX Request on API

I am using jQuery ajax to send request to some API. Due to the CORS policy I got a CORS error on the browser's console

Here's by code

$.ajax({
        url: sendHere,//api url
        type: 'GET',
        contentType: 'text/plain',
        crossDomain: true,
        beforeSend: function(xhr){
            xhr.withCredentials = true;
        },
    }).done(function (result) {

        console.log(result);

    }).error(function (err) {
        //console.log(err);
    });

Error

'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://www.mywebsite.com' is therefore not allowed access.

I tried to solve this problem by installing a chrome extension to enable allow cross origin request. This extension somehow solved my problem and got a response from the api. But installing an extension is not good.

I also tried to make the request with JSONP(dataType:'jsonp') but the response given by the api is not in json format, it is string so it gives an error.

Code with JSONP

$.ajax({
        url: sendHere,//api url
        type: 'GET',
        crossDomain: true,
        dataType:'jsonp',
    }).done(function (result) {

        console.log(result);

    }).error(function (err) {
        //console.log(err);
    });

Uncaught ReferenceError: E0002 is not defined
where "E0002" is the response string from the api

!!!PLEASE HELP!!!