我正在寻找一种方法，当鼠标悬停在元素上时，显示svg圆圈中的alt文本：结果
我正在使用这个javascrip代码，但我无法让它工作：

var PageTitle = document.getElementsByClassName("btn");
var MenuPageTitle = document.getElementById("pagetitle");
for (var i = 0; i < PageTitle.length; i++) {
PageTitle[i].addEventListener("mouseover", function() {
var alt = this.alt;
MenuPageTitle.textContent = alt;
});
}

有什么想法吗？
是对该小提琴示例的修改：https://jsfiddle.net/ywljkgah/1/ 我使用GetElementsByCassName而不是getelementsbytagname。我认为问题可能是在脚本的前面使用了mouseover addeventlistener。但我如何“结合”这两种用途呢？

var allCircles = document.querySelectorAll("circle");

// Add an click handler to every circle that
// adds the class "active" to the clicked circle.
allCircles.forEach(element => {
  element.addEventListener("click", clickHandler);
  element.addEventListener("mouseover", mouseoverHandler);
  element.addEventListener("mouseout", mouseoutHandler);
});

function clickHandler(evt) {
  // Clear current selection (remove class "active" from any circle)
  allCircles.forEach((circle) => circle.classList.remove("active"));
  // Mark clicked circle selected
  evt.target.classList.add("active");
  // Clear any currently highlighted lines
  clearHighlightedLines();
}

function mouseoverHandler(evt) {
  let activeCircle = document.querySelector("circle.active");
  let hoveredCircle = evt.target;
  if (activeCircle && (activeCircle != hoveredCircle)) {
    // Get the line that has classes matching both the actibve and hovered circle
    let line = document.querySelector("line." + activeCircle.id + "." + hoveredCircle.id);
    // Add the class "highlight" to that line
    if (line)
      line.classList.add("highlight");
  }
}

function mouseoutHandler(evt) {
  clearHighlightedLines();
}

function clearHighlightedLines() {
  // Find the line with class "highlight" (if any)
  var line = document.querySelector("line.highlight");
  // Remove the class "highlight"
  if (line)
    line.classList.remove("highlight");
}

var PageTitle = document.getElementsByClassName("btn");
var MenuPageTitle = document.getElementById("pagetitle");

for (var i = 0; i < PageTitle.length; i++) {
  PageTitle[i].addEventListener("mouseover", function() {
    var alt = this.alt;
    MenuPageTitle.textContent = alt;
  });
}

:root {
  --color-1: #F2B705;
  --color-2: #C30F0E;
  --color-3: #264ABA;
  --color-4: #009CD2;
  --color-5: #E25727;
  --color-11: #C29204;
  --color-22: #990B0B;
  --color-33: #172E73;
  --color-44: #006B8E;
  --color-55: #BA4620;
}

# c1 {

  fill: var(--color-1);
}

# c2 {

  fill: var(--color-2);
}

# c3 {

  fill: var(--color-3);
}

# c4 {

  fill: var(--color-4);
}

# c5 {

  fill: var(--color-5);
}

.cls-7 {
  fill: none;
}

# c1.active {

  stroke: var(--color-11);
  stroke-width: 21.5;
}

# c2.active {

  stroke: var(--color-22);
  stroke-width: 21.5;
}

# c3.active {

  stroke: var(--color-33);
  stroke-width: 21.5;
}

# c4.active {

  stroke: var(--color-44);
  stroke-width: 21.5;
}

# c5.active {

  stroke: var(--color-55);
  stroke-width: 21.5;
}

# c1.circle:hover:not(.active) {

  stroke: var(--color-11);
  stroke-width: 21.5;
}

# c2.circle:hover:not(.active) {

  stroke: var(--color-22);
  stroke-width: 21.5;
}

# c3.circle:hover:not(.active) {

  stroke: var(--color-33);
  stroke-width: 21.5;
}

# c4.circle:hover:not(.active) {

  stroke: var(--color-44);
  stroke-width: 21.5;
}

# c5.circle:hover:not(.active) {

  stroke: var(--color-55);
  stroke-width: 21.5;
}

circle.btn1:hover:not(.active) {
  stroke: var(--color-11);
  stroke-width: 21.5;
}

circle.btn2:hover:not(.active) {
  stroke: var(--color-22);
  stroke-width: 21.5;
}

circle.btn3:hover:not(.active) {
  stroke: var(--color-33);
  stroke-width: 21.5;
}

circle.btn4:hover:not(.active) {
  stroke: var(--color-44);
  stroke-width: 21.5;
}

circle.btn5:hover:not(.active) {
  stroke: var(--color-55);
  stroke-width: 21.5;
}

line {
  stroke: #c1c1c1;
  stroke-width: 22;
}

line.highlight {
  stroke: black;
}

/*
circle.active {
    stroke: red;
    stroke-width: 11.5;
}

* /

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="-10 -10 940 910">
   <defs>
    <style></style>
  </defs>
       <polygon id="fem-kant" class="cls-7" points="456.29 7.49 898.87 329.05 729.82 849.33 182.76 849.33 13.71 329.05 456.29 7.49"/>
      <line class="c3 c5" x1="656.32" y1="748.57" x2="133.5" y2="368.62"/>
      <line class="c2 c4" x1="258.55" y1="747.22" x2="779.33" y2="368.43"/>
      <line class="c1 c4" x1="258.55" y1="747.22" x2="457.43" y2="133.5"/>
      <line class="c1 c3" x1="457.43" y1="133.5" x2="657.03" y2="748.57"/>
      <line class="c5 c2" x1="133.5" y1="368.62" x2="779.33" y2="368.43"/>
      <line class="c1 c2" x1="779.33" y1="368.43" x2="457.43" y2="133.5"/>
      <line class="c2 c3" x1="779.33" y1="368.43" x2="657.03" y2="748.57"/>
      <line class="c3 c4" x1="258.55" y1="747.22" x2="657.03" y2="748.57"/>
      <line class="c4 c5" x1="258.55" y1="747.22" x2="133.5" y2="368.62"/>
      <line class="c5 c1" x1="133.5" y1="368.62" x2="457.43" y2="133.5"/>
  <a href="#0">
      <circle id="c1" class="btn1 btn" alt="one" cx="455.9" cy="133.5" r="133" data-Name="shape 1" data-tabindex="0" />
        </a>
  <a href="#0">
      <circle id="c2" class="btn2 btn" alt="two" cx="779.33" cy="368.43" r="133" data-Name="shape 2" data-tabindex="0" />
            </a>
            <a href="#0">
                <circle id="c3" class="btn3 btn" alt="three" cx="656.32" cy="748.57" r="133" data-Name="shape 3" data-tabindex="0" />
            </a>
  <a href="#0">
      <circle id="c4" class="btn4 btn" alt="four" cx="256.18" cy="748.57" r="133" data-Name="shape 4" data-tabindex="0" />
            </a>
            <a href="#0">
                <circle id="c5" class="btn5 btn" alt="Application" cx="133.5" cy="368.62" r="133" data-Name="shape 5" data-tabindex="0" />
            </a>
<script></script>
    </svg>
<p id="pagetitle"> </p>