如何在 JS 中插入变量

How to insert a var inside JS

本文关键字：插入 变量 JS      更新时间：2023-09-26

我想在"SP"所在的位置插入var "id"。可能吗？

var id = $(this).val();
    $("#select2").children("option[value^='SP_']").show();

上面的整个代码：

（我正在尝试这样做，因为我将添加另一个选择 （#select3），它将需要我在选项值上使用的 _1、_2、_3 过滤器。

<select name="select1" id="select1">
  <option value="vazio">Selecione um Estado</option>
  <option value="SP">São Paulo</option>
  <option value="PE">Pernambuco</option>
  <option value="GO">Goiás</option>
  <option value="BA">Bahia</option>
</select>
<select name="select2" id="select2">
  <option value="vazio">Selecione uma Cidade</option>
  <option value="SP_1">Cidade São Paulo</option>
  <option value="SP_2">Cidade São Paulo</option>
  <option value="SP_3">Cidade São Paulo</option>
  <option value="PE_1">Cidade Pernambuco</option>
  <option value="PE_2">Cidade Pernambuco</option>
  <option value="PE_3">Cidade Pernambuco</option>
  <option value="GO_1">Cidade Goiás</option>
  <option value="GO_2">Cidade Goiás</option>
  <option value="BA_1">Cidade Bahia<option>
</select>
<script>
$(document).ready(function() {
    $("#select2").children("option").hide();
});
$("#select1").change(function() {
    var id = $(this).val();
    $("#select2").children("option").hide();
    $("#select2").children("option[value^='SP_']").show();
});
</script>

看看它是否有效

普伦克

<!DOCTYPE html>
<html>
<body>
  <select id='mySelectBox'>
    <option value='SP_1'>test Val</option>
    <option value='UG_1'>test Val</option>
    <option value='SP_2'>test Val</option>
    <option value='UG_1'>test Val</option>
    <option value='SP_3'>test Val</option>
  </select>
<script>
  var myOpts = document.getElementById('mySelectBox').options;
  for(var i=0; i<myOpts.length; i++) {
    if(myOpts[i].value.indexOf('SP') > -1)
        myOpts[i].setAttribute('id', 'myId_' + i);
  }
</script>
</body>
</html>

结果

<select id="mySelectBox">
    <option value="SP_1" id="myId_0">test Val</option>
    <option value="UG_1">test Val</option>
    <option value="SP_2" id="myId_2">test Val</option>
    <option value="UG_1">test Val</option>
    <option value="SP_3" id="myId_4">test Val</option>
</select>

试试吧：

<script>
           $(document).ready(function() {
            $("<select id='select3'><option></option></select>").appendTo("body");
               var id = 1;
               $("#select3").children().attr({id:"SP_" + id}).text("SP_" + id);
           });
</script>
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