Javascript 链接 window.onload 函数

Question

我有一个 javascript 函数，可以获取数据集数值并将其附加到 XMLhttprequest 参数。它必须运行 onload，因为内容是通过 php 动态打印的。

我现在正在尝试为打印的元素创建一个简单的轮播，并发现链接 onload 函数有些困难。

我发现为任何破坏第一个 onload 函数的内容创建一个额外的 onload 函数。我在这里能做什么？

function userData() {
  let infoWrap = document.querySelector(".agent-detail-info").dataset.id;
  console.log(infoWrap);
  return infoWrap;
}
window.onload = userData;

window.onload = () => {
  const request = new XMLHttpRequest();
  request.open(
    "GET",
    `url&usertolookup=${userData()}`
  );

  request.onload = function () {
    let response = request.response;
    let parsedData = JSON.parse(response);
    console.log(parsedData);

    let testimonials = parsedData.data.testimonials.details;

    testimonials.forEach((testimonial, index) => {
      const testimonialWrap = document.querySelector(".testimonials");
      // Create testimonials container
      let innerTestimonials = document.createElement("div");
      innerTestimonials.className = "inner-testimonial-container";
      testimonialWrap.appendChild(innerTestimonials);

      // Create star rating container
      let starWrap = document.createElement("div");
      starWrap.className = "testimonial-stars";
      innerTestimonials.appendChild(starWrap);

      // Create Testimonial Content
      let innerTestimonialParagraph = document.createElement("p");
      innerTestimonials.appendChild(innerTestimonialParagraph);

      // Create Testimonial Signature
      let innerTestimonialSignature = document.createElement("address");
      innerTestimonials.appendChild(innerTestimonialSignature);

      // Loop through rating value and create elements
      let rating = testimonial.rating;
      for (let i = 0; i < rating; i++) {
        let star = document.createElement("i");
        star.className = "fa fa-star";
        starWrap.appendChild(star);
      }

      // Insert Testimonial Content
      let testimonialText = testimonial.Testimonial;
      innerTestimonialParagraph.innerHTML = testimonialText;

      // Insert Testimonial Signature
      let signature = testimonial.Signature;
      innerTestimonialSignature.innerHTML = signature;
    });
  };
  request.send();
};

测试轮播（已尝试使用事件侦听器而不是内联 onclick 进行替代，并且无法访问通过响应打印的元素（由于 dom 加载后打印元素而返回未定义））

let tabIndex = 1;

function nextTestimonial(n) {
  testimonialSlide((tabIndex += n));
}

function currentTestimonial(n) {
  testimonialSlide((tabIndex = n));
}

function testimonialSlide(n) {
  let innerTestimonials = document.querySelectorAll(
    ".inner-testimonial-container"
  );

  if (n > innerTestimonials.length) {
    tabIndex = 1;
  }
  if (n < 1) {
    tabIndex = innerTestimonials.length;
  }
  for (let i = 0; i < innerTestimonials.length; i++) {
    innerTestimonials[i].style.display = "none";
  }
  innerTestimonials[tabIndex - 1].style.display = "block";
}

随机尝​​试链接 onload 函数（这会破坏响应）

window.onload = () => {
  const innerTestimonialsNew = document.querySelectorAll(
    ".inner-testimonial-container"
  );
  console.log(innerTestimonialsNew);
};