jquery ajax 'Authorization' 'Bearer' 'Basic'

https://stackoverflow.com/questions/5507234/use-basic-authentication-with-jquery-and-ajax
Method 1:

var uName="abc";
var passwrd="pqr";

$.ajax({
    type: '{GET/POST}',
    url: '{urlpath}',
    headers: {
        "Authorization": "Basic " + btoa(uName+":"+passwrd);
    },
    success : function(data) {
      //Success block  
    },
   error: function (xhr,ajaxOptions,throwError){
    //Error block 
  },
});

Method 2:

var uName="abc";
var passwrd="pqr";

$.ajax({
    type: '{GET/POST}',
    url: '{urlpath}',
     beforeSend: function (xhr){ 
        xhr.setRequestHeader('Authorization', "Basic " + btoa(uName+":"+passwrd)); 
    },
    success : function(data) {
      //Success block 
   },
   error: function (xhr,ajaxOptions,throwError){
    //Error block 
  },
});

Method 3:

var uName="abc";
var passwrd="pqr";

$.ajax({
    type: '{GET/POST}',
    url: '{urlpath}',
    username:uName,
    password:passwrd, 
    success : function(data) {
    //Success block  
   },
    error: function (xhr,ajaxOptions,throwError){
    //Error block 
  },
});

https://stackoverflow.com/questions/14010851/set-request-header-jquery-ajax

$.ajax({
url: 'https://api.sandbox.slcedu.org/api/rest/v1/students/test1',
type: 'GET',
beforeSend: function (xhr) {
    xhr.setRequestHeader('Authorization', 'Bearer t-7614f875-8423-4f20-a674-d7cf3096290e');
},
data: {},
success: function () { },
error: function () { },
});

$.ajaxSetup({
    beforeSend: function(xhr) {
        xhr.setRequestHeader('Authorization', '...');
    }
});