使用php或javascript重新加载选项值

有没有办法用php或javascript在select中重新加载一些选项值？ 因此，当用户更改一个“选择”的值时，其他两个选择应该从值更改

例如： 你必须选择有多少成年人要去旅行。（最多6人） 所以你选择4 当您选择了其他2个选项（适用于儿童和婴儿）后，更改为剩余的数量（此处为2）

因此，当您在“儿童”选项中选择1时，婴儿将变为1

我原以为这样做会奏效，但我错了

<select name="dpl_volwassenen" id="dpl_volwassenen" onchange="getPersonen(this)">
                         <script type="text/javascript">
         for (i=0; i<=6; i++){
         myOption=new Option(i, i);
         document.getElementById('dpl_volwassenen').options[i]=myOption;
         }
         var aantal = 6;
                     function getPersonen($int_aantal){

                         aantal = aantal - $int_aantal.value;

                         for (i=0; i<=aantal; i++){
                         myOption=new Option(i, i);
                         document.getElementById($int_aantal.id).dpl_volwassenen.options[i]=myOption;
                         }
                     }
                        </script>
                        </select></td>
                </tr>
                <tr>
                    <td>
                        <select name="dpl_kinderen" id="dpl_kinderen" onchange="getPersonen(this)">
                        </select>
                    </td>
                </tr>
                <tr>
                    <td>
                        <select name="dpl_babys" id="dpl_babys" onchange="getPersonen(this)">
                    </select>
                    </td>
                </tr>

对于（i=0；i什么是
$int\u aantal
？PHP？您的浏览器不可能知道这一点。
应该可以帮助您。
您想要这样的东西吗

<script type="text/javascript">

  window.onload = function () {
    // Assign events in window.onload

    // Get references to all the <select>s
    volwassenenSelect = document.getElementById('dpl_volwassenen');
    kinderenSelect = document.getElementById('dpl_kinderen');
    babysSelect = document.getElementById('dpl_babys');

    volwassenenSelect.onchange = function () {
      var kOldSelected, bOldSelected, i, newOption;
      // Get the values of the other two selects
      kOldSelected = kinderenSelect.selectedIndex;
      bOldSelected = babysSelect.selectedIndex;
      // When volwassenen is changed, you need to update the other lists
      if (kinderenSelect.options.length > 0) {
        // kinderenSelect already has some options
        if (kinderenSelect.options.length < volwassenenSelect.selectedIndex + 1) {
          // we are adding more options
          for (i = kinderenSelect.options.length; i <= volwassenenSelect.selectedIndex; i++) {
            kinderenSelect.options[i] = new Option(i, i);
          }
        } else {
          // we are removing some options
          if (kOldSelected > volwassenenSelect.selectedIndex) {
            // if the selected option was greater than the number of new options, set it to the last option
            kinderenSelect.selectedIndex = volwassenenSelect.selectedIndex;
          }
          for (i = kinderenSelect.options.length - 1; i > volwassenenSelect.selectedIndex; i--) {
            kinderenSelect.removeChild(kinderenSelect.options[i]);
          }
        }
      } else {
        // kinderenSelect has no options yet, add volwassenenSelect.selectedIndex options
        for (i = 0; i <= volwassenenSelect.selectedIndex; i++) {
          kinderenSelect.options[i] = new Option(i, i);
        }
      }
      if (babysSelect.options.length > 0) {
        // babysSelect already has some options
        if (babysSelect.options.length < volwassenenSelect.selectedIndex + 1) {
          // we are adding more options
          for (i = babysSelect.options.length; i <= volwassenenSelect.selectedIndex; i++) {
            babysSelect.options[i] = new Option(i, i);
          }
        } else {
          // we are removing some options
          if (bOldSelected + kinderenSelect.selectedIndex > volwassenenSelect.selectedIndex) {
            // make sure the total of kinderenSelect + babysSelect does not excede volwassenenSelect
            babysSelect.selectedIndex = volwassenenSelect.selectedIndex - kinderenSelect.selectedIndex;
          } else if (bOldSelected > volwassenenSelect.selectedIndex) {
            // if the selected option was greater than the number of new options, set it to the last option
            babysSelect.selectedIndex = volwassenenSelect.selectedIndex;
          }
          for (i = babysSelect.options.length - 1; i > volwassenenSelect.selectedIndex; i--) {
            babysSelect.removeChild(babysSelect.options[i]);
          }
        }
      } else {
        // babysSelect has no options yet, add volwassenenSelect.selectedIndex options
        for (i = 0; i <= volwassenenSelect.selectedIndex; i++) {
          babysSelect.options[i] = new Option(i, i);
        }
      }
    };

    // These two functions make sure the total of kinderenSelect + babysSelect does not excede volwassenenSelect
    kinderenSelect.onchange = function () {
      if (babysSelect.selectedIndex > volwassenenSelect.selectedIndex - kinderenSelect.selectedIndex) {
        babysSelect.selectedIndex = volwassenenSelect.selectedIndex - kinderenSelect.selectedIndex;
      }
    };
    babysSelect.onchange = function () {
      if (kinderenSelect.selectedIndex > volwassenenSelect.selectedIndex - babysSelect.selectedIndex) {
        kinderenSelect.selectedIndex = volwassenenSelect.selectedIndex - babysSelect.selectedIndex;
      }
    };

  };    

</script>
<table>
  <tr>
    <td>Volwassenen</td>
    <td>
      <select id="dpl_volwassenen" name="dpl_volwassenen">
        <option value="0">0</option>
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
        <option value="4">4</option>
        <option value="5">5</option>
        <option value="6">6</option>
      </select>
    </td>
  </tr>
  <tr>
    <td>Kinderen</td>
    <td>
      <select id="dpl_kinderen" name="dpl_kinderen"></select>
    </td>
  </tr>
  <tr>
    <td>Babys</td>
    <td>
      <select id="dpl_babys" name="dpl_babys"></select>
    </td>
  </tr>
</table>


window.onload=函数（）{
//在window.onload中分配事件
//获取所有s的引用
volwassenenSelect=document.getElementById（'dpl_volwassenen'）；
kindenselect=document.getElementById（'dpl_kinderen'）；
babyselect=document.getElementById（'dpl_babys'）；
volwassenneselect.onchange=函数（）{
var kOldSelected、bOldSelected、i、newOption；
//获取其他两个选择的值
kOldSelected=kindenselect.selectedIndex；
bOldSelected=BabySelected.selectedIndex；
//更改volwassenen后，需要更新其他列表
如果（kindenselect.options.length>0）{
//Kindenselect已经有了一些选择
if（kindensenselect.options.lengthvolwassenneselect.selectedIndex；i--）{
kindenselect.removeChild（kindenselect.options[i]）；
}
}
}否则{
//kinderenSelect还没有选项，请添加volwassenenSelect.selectedIndex选项
对于（i=0；i=0）{
//BabySelect已经有了一些选项
if（babyselect.options.lengthvolwassenenSelect.selectedIndex）{
//如果所选选项大于新选项数，请将其设置为最后一个选项
babyselect.selectedIndex=volwassenneselect.selectedIndex；
}
对于（i=babysSelect.options.length-1；i>volwassenneselect.selectedIndex；i--）{
babyselect.removeChild（babyselect.options[i]）；
}
}
}否则{
//BabySelect尚未有任何选项，请添加VolwassenneSelect.selectedIndex选项
对于（i=0；i volwassenneselect.selectedIndex-kindensenselect.selectedIndex）{
babyselect.selectedIndex=volwassenneselect.selectedIndex-kindensenselect.selectedIndex；
}
};
babyselect.onchange=函数（）{
如果（KinderSenseSelect.selectedIndex>VolwassenSenseSelect.selectedIndex-BabySelect.selectedIndex）{
KinderSenselect.selectedIndex=Volwassensenselect.selectedIndex-BabySelect.selectedIndex；
}
};
};    
沃瓦森
0
1.
2.
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4.
5.
6.
幼稚的
婴儿
这里是另一种使用方法

        <script language='javascript'>
        var kinderen = new Array();
        var babys = new Array();
        var max_aantal = 6;
            function getPersonen(sParentBox, sChildBox){
                //get the value of the selected option

                var sParentValue = document.getElementById(sParentBox).value;

                max_aantal =max_aantal - sParentValue;
                alert(max_aantal);
                //load the appropriate event list to the option box
                 var theSel  = document.getElementById(sChildBox);

                //clear previous options
                theSel.options.length = null;


                //handle if there is no value
                if (sParentValue == ''){alert("exiting"); return;}
                  if (sParentBox == "dpl_volwassenen") {

                      for(i=0; i<=max_aantal;i++){
                            kinderen.push(i);
                          }
                    oTargetArray = kinderen;
                    }else if(sParentBox == "dpl_kinderen"){
                        for(i=0; i<=max_aantal;i++){
                            babys.push(i);
                          }
                      oTargetArray = babys;
                    }

  //split the array values by the separator
 // var arrList     = oTargetArray[sParentValue].split(",");
 alert(oTargetArray.length);
//loop thru the array of options to add them to the dropdown
for (x=0; x < oTargetArray.length; x++)
  {
    var newOpt     = new Option(oTargetArray[x], oTargetArray[x]);//(theText,theValue);
    var selLength  = theSel.length;
    theSel.options[selLength] = newOpt;
  }//next
}//end func

</script>


var kinderen=新数组（）；
var babys=新数组（）；
var max_aantal=6；
函数getPersonen（sParentBox、sChildBox）{
//获取所选选项的值
var sParentValue=document.getElementById（sParentBox.value）；
max_aantal=max_aantal-sParentValue；
警报（最大值）；
//将适当的事件列表加载到选项框中
var theSel=document.getElementById（sChildBox）；
//清除以前的选项
theSel.options.length=null；
//如果没有值，则处理
if（sParentValue=''）{alert（“exiting”）；return；}
如果（sParentBox==“dpl_volwassenen”）{
对于（i=0；你想在谷歌上搜索的短语是“条件下拉javascript”，有一百万种方法可以做到这一点；-）事实上，JS变量允许使用
$
。我建议避免使用它，但这是允许的。这更像是在添加元素时，onchange函数再次启动。因此，在第一次通过循环后，他再次启动该函数。是的，这就是我要寻找的。