Question

在“ currentTarget”处，运行代码时出现错误。

我尝试研究问题，但找不到任何有效的方法

// London is active by defult
document.getElementById("London").style.display = "block";
event.currentTarget.className += " active";

function openCity(cityName) {

  // Get all elements with class="tabcontent" and hide them
  let tabcontent = document.getElementsByClassName("tabcontent");
  for (i = 0; i < tabcontent.length; i++) {
    tabcontent[i].style.display = "none";
  }

  // Get all elements with class="tablinks" and remove the class "active"
  let tablinks = document.getElementsByClassName("tablinks");
  for (i = 0; i < tablinks.length; i++) {
    tablinks[i].className = tablinks[i].className.replace("active", "");
  }

  // Show the current tab, and add an "active" class to the button that opened the tab
  document.getElementById(cityName).style.display = "block";
  event.currentTarget.className += "active";
}

index.js：12未捕获的TypeError：无法读取的属性“ currentTarget” 在index.js：12上未定义

Answer 1

此代码都不在事件侦听器中，因此没有event变量。我猜想您要将类添加到与您设置样式相同的元素中。

与其在className字符串上进行操作，不如在classList上使用函数。

// London is active by defult
var defaultElement = document.getElementById("London");
defaultElement.style.display = "block";
defaultElement.classList.add("active");

function openCity(cityName) {

  // Get all elements with class="tabcontent" and hide them
  let tabcontent = document.getElementsByClassName("tabcontent");
  for (let i = 0; i < tabcontent.length; i++) {
    tabcontent[i].style.display = "none";
  }

  // Get all elements with class="tablinks" and remove the class "active"
  let tablinks = document.getElementsByClassName("tablinks");
  for (let i = 0; i < tablinks.length; i++) {
    tablinks[i].classList.remove("active");
  }

  // Show the current tab, and add an "active" class to the button that opened the tab
  var newElement = document.getElementById(cityName);
  newElement.style.display = "block";
  newElement.classList.add("active");
}

Answer 2

添加到您在html代码中定义的函数参数事件例如：onclick="openCity(event)"

如何修复无法读取未定义错误的属性“ currentTarget”

2 个答案: