javascript - 将单选按钮链接到下拉菜单

Question

我希望在不使用任何 if/else/while/for/任何控制流语句的情况下，只使用普通的 javascript 来完成这个小项目，但我似乎遇到了问题。我只是想将单选按钮连接到下拉菜单，以便在单击一个按钮时突出显示另一个按钮。例如，现在我已经这样做了，当您使用 setRB() 函数从下拉菜单中选择一个项目时，它会将相应的单选按钮设置为真。

我现在想让单选按钮设置为 true 到相应的下拉菜单项。这可以通过上述条件完成，还是我需要使用控制流语句(我相信它们都是这样叫的)。

谢谢。

function setRb() {
  //Point to options list
  //var e = document.getElementById('selColors');
  var e = document.jon.resistors;
  //Get value of color selected
  var s = e.options[e.selectedIndex].value;
  //Now get radio button obect and check it
  var c = document.getElementById(s);
  c.checked = true;
}
function setList(radio) {
  alert(radio); 
}

<form name=jon>
    <select id="selColors" name="resistors">
      <option value="rbBlack">Black</option>
      <option value="rbBlue">Blue</option>
      <option value="rbBrown">Brown</option>
      <option value="rbGrey">Grey</option>
      <option value="rbGreen">Green</option>
      <option value="rbOrange">Orange</option>
      <option value="rbRed">Red</option>
      <option value="rbViolet">Violet</option>
      <option value="rbYellow">Yellow</option>
      <option value="rbWhite">White</option>
    </select>
    <input onclick="setRb()" type="button" value="Submit">


<div>
    <table>
    <tr>
    <td><input onclick="setList(this.value)" id="rbBlack" value="Black" type="radio" name="colors" />Black</td>
    <td><input onclick="setList(this.value)" id="rbBlue" value="Blue" type="radio" name="colors" />Blue</td>
    <td><input onclick="setList(this.value)" id="rbBrown" value="Brown" type="radio" name="colors" />Brown</td>
    <td><input onclick="setList(this.value)" id="rbGrey" value="Grey" type="radio" name="colors" />Grey</td>
    <td><input onclick="setList(this.value)" id="rbGreen" value="Green" type="radio" name="colors" />Green</td>
    <td><input onclick="setList(this.value)" id="rbOrange" value="Orange" type="radio" name="colors" />Orange</td>
    <td><input onclick="setList(this.value)" id="rbRed" value="Red" type="radio" name="colors" />Red</td>
    <td><input onclick="setList(this.value)" id="rbViolet" value="Violet" type="radio" name="colors" />Violet</td>
    <td><input onclick="setList(this.value)" id="rbYellow" value="Yellow" type="radio" name="colors" />Yellow</td>
    <td><input onclick="setList(this.value)" id="rbWhite"value="White" type="radio" name="colors" />White</td>
    </tr>
    </table>
</div>

Answer 1

是的，这是可能的。

访问具有所选选项值的选项:

document.querySelector("option[value='x']")

function setRb() {
  //Point to options list
  //var e = document.getElementById('selColors');
  var e = document.jon.resistors;
  //Get value of color selected
  var s = e.options[e.selectedIndex].value;
  //Now get radio button obect and check it
  var c = document.getElementById(s);
  c.checked = true;
}

// Set current option null
var currOpt = null;

function setList(e) {
  // Value is the id of the clicked radio button
  var val = e.id;
  // Access current option
  currOpt = document.querySelector("option[value=" + val + "]");
  // Set current option "selected" 
  currOpt.setAttribute("selected", "");
}

<form name=jon>
  <select id="selColors" name="resistors">
    <option value="rbBlack">Black</option>
    <option value="rbBlue">Blue</option>
    <option value="rbBrown">Brown</option>
    <option value="rbGrey">Grey</option>
    <option value="rbGreen">Green</option>
    <option value="rbOrange">Orange</option>
    <option value="rbRed">Red</option>
    <option value="rbViolet">Violet</option>
    <option value="rbYellow">Yellow</option>
    <option value="rbWhite">White</option>
  </select>
  <input onclick="setRb()" type="button" value="Submit">
</form>

<div>
  <table>
    <tr>
      <td>
        <input onclick="setList(this)" id="rbBlack" value="Black" type="radio" name="colors" />Black</td>
      <td>
        <input onclick="setList(this)" id="rbBlue" value="Blue" type="radio" name="colors" />Blue</td>
      <td>
        <input onclick="setList(this)" id="rbBrown" value="Brown" type="radio" name="colors" />Brown</td>
      <td>
        <input onclick="setList(this)" id="rbGrey" value="Grey" type="radio" name="colors" />Grey</td>
      <td>
        <input onclick="setList(this)" id="rbGreen" value="Green" type="radio" name="colors" />Green</td>
      <td>
        <input onclick="setList(this)" id="rbOrange" value="Orange" type="radio" name="colors" />Orange</td>
      <td>
        <input onclick="setList(this)" id="rbRed" value="Red" type="radio" name="colors" />Red</td>
      <td>
        <input onclick="setList(this)" id="rbViolet" value="Violet" type="radio" name="colors" />Violet</td>
      <td>
        <input onclick="setList(this)" id="rbYellow" value="Yellow" type="radio" name="colors" />Yellow</td>
      <td>
        <input onclick="setList(this)" id="rbWhite" value="White" type="radio" name="colors" />White</td>
    </tr>
  </table>
</div>