Javascript 如果单击特定键，我如何每 5 秒检查一次？

Question

在这种情况下，如果单击右箭头按钮，我如何每 5 秒检查一次？这是我试过的。它只工作一次，永远不会再次检查。我做错了什么？

setInterval(KeyPressed, 5000);

window.onkeydown = KeyPressed;

function KeyPressed(k) {

    if (k.keyCode == 39) {
        alert("Right Arrow");
    }

}

Answer 1

也许是这个？

检查最后点击的键是否是箭头

var lastKey = "", tId = setInterval(testKey, 5000);

window.onkeydown = KeyPressed;

function KeyPressed(k) {
  lastKey = k.keyCode;
}
function testKey() {
  if (lastKey == 39) {
    console.log("Arrow pressed as last key in the last 5 secs");
    lastKey=""; // clear it for next time
  }
}

检查箭头是否在最后 5 秒内被点击

var lastKey = "", tId = setInterval(testKey, 5000), arrow = "";

window.onkeydown = KeyPressed;

function KeyPressed(k) {
  lastKey = k.keyCode;
  if (lastKey == 39) {
    arrow = new Date();
    console.log("pressed arrow");
  }  
}
function testKey() {
  if (arrow) {
    console.log("Arrow pressed at least once in the last 5 secs - at "+arrow);
  }
  arrow="";
}