关于javascript：Access-Control-Allow-Origin不允许使用Origin null

Origin null is not allowed by Access-Control-Allow-Origin

本问题已经有最佳答案，请猛点这里访问。

json响应在{"userName":"clevermeal835","userRole":"Participant"}中

我收到一条警报消息，但是在阅读响应时我收到错误：

XMLHttpRequest cannot load the url Origin null is not allowed by
Access-Control-Allow-Origin.

如果我从命令提示符运行代码

--disable-web-security

我得到了回应。
任何人都可以使用命令提示符帮助我解决此问题。
以下代码。

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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<script type="text/javascript" src="Scripts/jquery-1.4.2.min.js">

$(document).ready(
function() {
$("#jsonpbtn2").click(function() {
var uid ="clevermeal835";
var pwd ="Welcome_1";
var userType ="participant";
var surl="http://localhost:8080/RESTlet_WS/MobiSignIn/{"userName":""+uid+"","password":""+pwd+"","userType":""+userType+""}/";

$.ajax({
type : 'GET',
contentType:"application/json; charset=utf-8",
url : surl,
dataType : 'json',
headers : {Accept :"application/json","Access-Control-Allow-Origin" :"*"},
crossDomain : true,
success :SucceedFunc ,
error : function(data, textStatus, errorThrown) {
console.log("error"+' '+JSON.stringify(data) + textStatus + errorThrown);}
});

function SucceedFunc(data) {
alert("success");
var userName = data.userName;
alert(userName);
}
});
});

</head>
<body>
<input id="jsonpbtn2" type="submit" value="button" />
</body>
</body>
</html>