firstPHP/public/js/ajax.js

function ajaxRequest() {
   const request = new XMLHttpRequest();
   request.open("GET", "/admin/form-add-fields");
   request.addEventListener("load", () => {
      const responseText = request.responseText;
      const targetElement = document.getElementById("buttonAdd");
      const divElement = document.createElement("div");
      divElement.classList.add("form-control");
      divElement.style.backgroundColor = "#bbbbbb";
      divElement.innerHTML = responseText;
      targetElement.insertAdjacentElement("beforebegin", divElement);

      const deleteButton = document.createElement("button");
      deleteButton.textContent = "Delete";
      deleteButton.addEventListener("click", () => {
         divElement.remove();
      });
      divElement.appendChild(deleteButton);
   });
   request.send();
}

function getValueSelect(){
   var selectValue = document.getElementById("selectID").value
   var request = new XMLHttpRequest();
   let button = document.getElementById("buttonAdd");
   let count = parseInt(button.dataset.count) + 1;
   button.dataset.count = count;
   console.log(count);
   request.open("GET", "/admin/set-value-select?value=" + selectValue + "&count=" + count, true)
   request.addEventListener("load", () => {
      var responseText = request.responseText;
      var targetElement = document.getElementById("buttonAdd");
      var divElement = document.createElement("div");
      divElement.classList.add("form-control form-new-block");
      divElement.innerHTML = responseText;
      targetElement.insertAdjacentElement("beforebegin", divElement);

      const deleteButton = document.createElement("button");
      deleteButton.textContent = "X";
      deleteButton.classList = 'btn-danger delete-button';
      deleteButton.addEventListener("click", () => {
         divElement.remove();
      });
      divElement.appendChild(deleteButton);
   });
   request.send()
}
function getIdBlock(){

}