JavaScript-在数组中查找元素，并从用户提示中处理null

JavaScript - Lookup element in array and handle nulls from user prompt

本文关键字：用户 提示 处理 null 数组 查找 元素 JavaScript-      更新时间：2023-09-26

我是JavaScript的新手，我正在做这个颜色猜测游戏作为一项任务。我的剧本在下面。我尝试了很多我能想到的不同方式，但我就是无法做到。

总之，我有两个问题。

  1. 如何检查用户键入的值是否存在于数组中
  2. 如果用户在没有值的情况下单击"确定"，我如何确保排除空值？在此处输入代码

脚本在下面。如果你运行该程序，它将显示用户猜测的答案（仅用于测试）。如果用户猜测正确，则页面颜色将为该颜色。任何帮助都将不胜感激。

<DOCTYPE! HTML>
<HTML>
<HEAD>
<TITLE>Color Guessing Game</TITLE>
   </HEAD>
     <body onload="do_game()">
      <script type="text/javascript">
       var target;
       var target_index;
       var guess_input;
       var finished = false;
        var guess_input_text;
       var guesses = 0
        var color= ["Blue","Coral","Cyan","Fuchsia","Gold","Lavender","Lime","Red","Tan"];
         var myBody=document.getElementsByTagName("body")[0];
         var check_color = colors.indexOf(guess_input);
        function do_game(){
        var random_number_integer = colors[Math.floor(Math.random() *  colors.length-1)];
        target = random_number_integer;
         alert(target);
        while (!finished) {
         guess_input_text = prompt("I am thinking of one these colors: 'n'n'n" + 
                                colors.toString() + 
                              "'n'n'n What color am I thinkning of?");
    guess_input = guess_input_text;
    guesses += 1;
    finsihed = check_guess(); 
    }
}
  function check_guess() {
       if (guess_input == null){
         alert("Type in a color.");
          return false;
}
if (guess_input > target){
    alert("Your input is alphabetically lower than mine!" +
            "'n'nPlease Try Again.'n'n");
        return false;
}
if (guess_input < target){
    alert("Your input is alphabetically higher than mine!" +
            "'n'nPlease Try Again.'n'n");
    return false;
}
alert("Yes!!!, the correct color was: " + target +
        "'n'n'n The Number of guesses:" + guesses +
        "'n'n'nGood Job'n'n'n");
myBody.style.background=guess_input;
return true;
 }
 </script>
 </body>
 </HTML>

答案1：使用indexOf：（文档）

答案2：https://stackoverflow.com/a/20533178/3603806

// check whether the array or string empty
function is_empty(obj){
	if (obj == null || (obj == '' && obj.length == 0)){
		return true;
	}
	else {
		return false;
	}
}
// check whether this elem is included in arr
function is_included(elem, arr){
    if (is_empty(arr) || is_empty(elem) || arr.toString().indexOf(elem) == -1){
        return false;
    }
    else {
        return true;
    }
}

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