嗨。我是编程新手，我正在尝试在 html 中创建一个搜索栏，将搜索输入存储为字符串

Answer 1

你错过了几件事。
首先，您需要解析输入字符串，以生成字符串数组。 第二个你

function test(){
    var a = document.getElementById('search').value;
    var b = "Apple, Banana";
    var ar = b.split(", "); // arrray of strings

    for (var c = 0; c <= 1; c++) {
      if (a.match(ar[c])){ // no innerHTML function
        document.getElementById('show').innerHTML = "You search " + "'" + ar[c] + "'";
        return; // return after match
      } else 
        document.getElementById('show').innerHTML = "ERROR.";            
    }
}

<i id="show"></i>//Output will show here//

<input id="search" type="text" placeholder="Search...">//Search Bar//
<button value="submit" onclick="return test()" type="submit">Search</button>