Question

我添加了按键监听器，但这不起作用。当“点击”的听众被调用时 - 工作正常。

这是代码：

var closeSave = document.getElementById("closeSave");
    closeSave.addEventListener("click", closeWindow);
    closeSave.addEventListener("keypress", closeWindowByEsc);

            // When the user clicks on <span> (x), close the modal
        var closeWindow = function() {
            saveModal.style.display = "none";
            loadModal.style.display = "none";
        }

    var closeWindowByEsc = function(){
    if (!e) e = window.event;
    var keyCode = e.keyCode || e.which;
    if (keyCode == '27'){
      closeWindow(e);
    }
  }

可能是什么问题？

Answer 1

问题是声明var func = function () { ...将var func;部分提升到范围顶部，但func未定义为function () { ...，直到达到该行。因此，当您附加事件处理程序时，这基本上就是发生的事情：

var closeSave = document.getElementById("closeSave");
var closeWindow;
var closeWindowByEsc;

// here, closeWindow and closeWindowByEsc are `undefined`
closeSave.addEventListener("click", closeWindow);
closeSave.addEventListener("keypress", closeWindowByEsc);

// When the user clicks on <span> (x), close the modal
closeWindow = function() {
  saveModal.style.display = "none";
  loadModal.style.display = "none";
}

closeWindowByEsc = function(e) {
  if (!e) e = window.event;
  var keyCode = e.keyCode || e.which;
  if (keyCode == '27') {
    closeWindow();
  }
}

你可以做两件事来解决这个问题：

移动实例化下面的addEventListener()：

var closeSave = document.getElementById("closeSave");

// When the user clicks on <span> (x), close the modal
var closeWindow = function() {
  saveModal.style.display = "none";
  loadModal.style.display = "none";
}

var closeWindowByEsc = function(e) {
  if (!e) e = window.event;
  var keyCode = e.keyCode || e.which;
  if (keyCode == '27') {
    closeWindow();
  }
}

closeSave.addEventListener("click", closeWindow);
closeSave.addEventListener("keypress", closeWindowByEsc);

或者你可以使用一个函数语句将实例化提升到作用域的顶部，而不是函数表达式：

var closeSave = document.getElementById("closeSave");

closeSave.addEventListener("click", closeWindow);
closeSave.addEventListener("keypress", closeWindowByEsc);

// When the user clicks on <span> (x), close the modal
function closeWindow() {
  saveModal.style.display = "none";
  loadModal.style.display = "none";
}

function closeWindowByEsc(e) {
  if (!e) e = window.event;
  var keyCode = e.keyCode || e.which;
  if (keyCode == '27') {
    closeWindow();
  }
}

Answer 2

您没有将事件e传递给您的函数。

var closeSave = document.getElementById("closeSave");
closeSave.addEventListener("click", closeWindow);
closeSave.addEventListener("keypress", function(e){
    if (!e) e = window.event;
    var keyCode = e.keyCode;
    if (keyCode == '27'){
        closeWindow();
    }
});

// When the user clicks on <span> (x), close the modal
function closeWindow() {
    saveModal.style.display = "none";
    loadModal.style.display = "none";
}

Esc事件监听器无法正常工作

2 个答案: