javascript - 执行函数 appear() 出现在 If 语句中

Question

//Blinking of the letter " X " on the Screen
function blink() {
  document.getElementById('blinkText').innerHTML = "";
  setTimeout("appear()", Math.random() * 3000);
}

//Re-Appearing of the letter " X " on the Screen
function appear() {
  document.getElementById('blinkText').innerHTML = "X";
  setTimeout("blink()", Math.random() * 3000);
  return true;
}

// Counts the number of times a space bar is hit
var hit = 0;
window.onload = function hitSpace() {
  document.body.onkeyup = function(e) {
    if (e.keyCode == 32) {
      hit = hit + 1;
      document.getElementById("count").innerHTML = hit;
    }
  }
  blink();
}

//To run function hitSpace() only when the letter "X" appears, else display 
alert

function checkForBlink() {
  if (appear() == true) {
    hitSpace();
  } else {
    alert("You are too slow!")
  }
}

基本上我不能做的是，当字母 X 出现在屏幕上时，我想使用函数 hitSpace() 进行计数，如果在字母 X 不存在时按下空格键，则显示一条警告消息。请帮助纠正我的功能 checkForBlink()

Answer 1

您不需要调用 hitSpace()。检查 X 是否存在于 onkeyup 函数中。

window.onload = function() {
  document.body.onkeyup = function(e) {
    if (e.keyCode == 32) {
      if (document.getElementById("blinkText").innerHTML == "X") {
        hit = hit + 1;
        document.getElementById("count").innerHTML = hit;
      } else {
        alert("Sorry, you're too slow");
      }
    }
  }
  blink();
}