checkKey在程序

Question

出于某种原因，当我在JavaScript中为checkKey函数添加Enter按钮值时，整个程序停止工作。我尝试在JavaScript中查找Enter按钮的正确数值，根据一些网站，这是13，但该程序仍然无法正常工作。救命啊！

HTML

  <button type="leftButton" onClick="leftClick()">Left</button>
  <p>Clicks: <a id="leftClicks">0</a></p>

  <button type="rightButton" onClick="rightClick()">Right</button>
  <p>Clicks: <a id="rightClicks">0</a></p>

  <input type="button" onClick="save()" value="save" />
  <p>Save: <a id="saveClicks"></a></p>

的JavaScript

// Left counter
var leftClicks = 0;
  function leftClick() {
    leftClicks += 1;
    document.getElementById('leftClicks').innerHTML = leftClicks;
  }

// Right counter
var rightClicks = 0;
  function rightClick() {
    rightClicks += 1;
    document.getElementById('rightClicks').innerHTML = rightClicks;
  }

// Save
function save() {
  document.getElementById('saveClicks').innerHTML = leftClicks + " " + rightClicks;
}

// L/R key actions
document.onkeydown = checkKey;
  function checkKey(e) {
    e = e || window.event;
    if (e.keyCode == '37') {
      leftClicks += 1;
      document.getElementById('leftClicks').innerHTML = leftClicks;
    } else if (e.keyCode == '39') {
      rightClicks += 1;
      document.getElementById('rightClicks').innerHTML = rightClicks;
    } else if (e.keyCode == '90') {
      leftClicks -= 1;
      document.getElementById('leftClicks').innerHTML = leftClicks;
    } else if (e.keyCode == '88') {
      rightClicks -= 1;
      document.getElementById('rightClicks').innerHTML = rightClicks;
    } else if (e.keyCode == '82') {
      leftClicks = 0;
      rightClicks = 0;
      document.getElementById('leftClicks').innerHTML = leftClicks;
      document.getElementById('rightClicks').innerHTML = rightClicks;
    } else if (e.keyCode == '13') {
      function save();
    }
  }

所以，问题是当我向程序添加以下代码行时，它会完全停止工作。那是为什么？

else if (e.keyCode == '13') {
  function save();
}

Answer 1

按下回车键时，要正确调用保存功能，您可以执行以下操作：

else if(e.keyCode == '13') {
    save();
}

在调用已声明的函数时，function这个词不应该存在。 如果您想要anonymous函数调用save，可以执行以下操作：

else if(e.keyCode == '13') {
    function(){
        save();
    }
}