JavaScript DOM makes server request

Question

When I load the page without the following js code, it runs fine, but when I create the html element using the DOM, how does it make a server request using the same page url,

const isHideVariants = document.querySelector("#hidevariants");
      const vehiclesList = document.querySelector(".brand-vehicles-list");

      let vehicles = <%- JSON.stringify(vehicles) %>;

      displayVehicles();

      function displayVehicles() {
        clearVehicles();
        vehicles.forEach((vehicle) => {
          const anchorTag = document.createElement("a");
          const img = document.createElement("img");
          const p = document.createElement("p");
          anchorTag.href = `/vehicles/${vehicle._id}`;
          anchorTag.classList.add("brand-vehicle");
          img.src = vehicle.thumbnail;
          img.alt = "vehicle thumbnail";
          p.textContent = vehicle.name;
          anchorTag.appendChild(img);
          anchorTag.appendChild(p);
          vehiclesList.appendChild(anchorTag);
        });
      }

      function clearVehicles() {
        while (vehiclesList.firstChild) {
          vehiclesList.removeChild(vehiclesList.firstChild);
        }
      }

I tested the code when I commented out the js DOM code and then it didn't make any other server requests

This is the first request

GET /brands/dodge 200 2109.074 ms - 16952

This is the second request that is triggered when I create the html DOM element

GET /brands/undefined 200 8297.877 ms - 16781

Answer 1

This GET request is sent with the src attribute tagged . And the value of src is undefined. This means that vehicle.thumbnail in your code is undefined.

ViewHow is the src attribute of the img tag implemented?