Javascript过滤表，如果只显示1行

Question

我到处寻找这个答案而无法找到解决方案。作为一个例子，我使用了w3schools。

＆＃13;

＆＃13;

function myFunction() {
  var input, filter, table, tr, td, i;
  input = document.getElementById("myInput");
  filter = input.value.toUpperCase();
  table = document.getElementById("myTable");
  tr = table.getElementsByTagName("tr");
  for (i = 0; i < tr.length; i++) {
    td = tr[i].getElementsByTagName("td")[0];
    if (td) {
      if (td.innerHTML.toUpperCase().indexOf(filter) > -1) {
        tr[i].style.display = "";
      } else {
        tr[i].style.display = "none";
      }
    }
  }
}

＆＃13;

* {
  box-sizing: border-box;
}

#myInput {
  background-image: url('/css/searchicon.png');
  background-position: 10px 10px;
  background-repeat: no-repeat;
  width: 100%;
  font-size: 16px;
  padding: 12px 20px 12px 40px;
  border: 1px solid #ddd;
  margin-bottom: 12px;
}

#myTable {
  border-collapse: collapse;
  width: 100%;
  border: 1px solid #ddd;
  font-size: 18px;
}

#myTable th,
#myTable td {
  text-align: left;
  padding: 12px;
}

#myTable tr {
  border-bottom: 1px solid #ddd;
}

#myTable tr.header,
#myTable tr:hover {
  background-color: #f1f1f1;
}

＆＃13;

<h2>My Customers</h2>

<input type="text" id="myInput" onkeyup="myFunction()" placeholder="Search for names.." title="Type in a name">

<table id="myTable">
  <tr class="header">
    <th style="width:60%;">Name</th>
    <th style="width:40%;">Country</th>
  </tr>
  <tr>
    <td>Alfreds Futterkiste</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Berglunds snabbkop</td>
    <td>Sweden</td>
  </tr>
  <tr>
    <td>Island Trading</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Koniglich Essen</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Laughing Bacchus Winecellars</td>
    <td>Canada</td>
  </tr>
  <tr>
    <td>Magazzini Alimentari Riuniti</td>
    <td>Italy</td>
  </tr>
  <tr>
    <td>North/South</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Paris specialites</td>
    <td>France</td>
  </tr>
</table>

＆＃13;

＆＃13;

＆＃13;

我的问题是，在我过滤结果并只显示一行后，我想添加另一个if / then语句。因此，如果显示1行然后警告（＆＃34;显示1行＆＃34;）;否则没有警报。希望这是有道理的。

Answer 1

为什么不添加一个计数器？

<script>
function myFunction() {
  var input, filter, table, tr, td, i;
  input = document.getElementById("myInput");
  filter = input.value.toUpperCase();
  table = document.getElementById("myTable");
  tr = table.getElementsByTagName("tr");
  var counter = 0;
  for (i = 0; i < tr.length; i++) {
    td = tr[i].getElementsByTagName("td")[0];
    if (td) {
      if (td.innerHTML.toUpperCase().indexOf(filter) > -1) {
        tr[i].style.display = "";
        counter ++;
      } else {
        tr[i].style.display = "none";
      }
    }       
  }
  if(counter == 1) alert('1 row displayed')
}
</script>