Call Custom API in Sitecore using JavaScript

Controller Logic here 
using Sitecore.Configuration;
using Sitecore.Data.Items;
using Sitecore.Mvc.Controllers;
using Sitecore.Resources.Media;
using Sitecore.SecurityModel;
using System.Web.Mvc;
public class ArticleDetailsController : SitecoreController
    {
       
        [HttpGet]
        public virtual ActionResult ArticleDetails()
        {
        //Read Query String values here
            // To Do Sitecore related activities here
         }
    }  

In JavaScript we will access

function ArticleDetails() {
 
   var HostUrl = "Your Host Url";  
   var xmlHttp = new XMLHttpRequest();
   var url = HostUrl + '/api/Sitecore/QuickPost/ArticlePost?QueryString
   xmlHttp.open("GET", url, false);
   xmlHttp.send(null);
   return xmlHttp.responseText;
}