创建动态下拉列表

Question

我在网上搜索相当长的一段时间以找到合适的解决方案，但迄今为止我还没有成功。

我试图达到的目标：我创建了一个省下载的动态下拉框。只要用户选择其中一个动态创建的条目，区域的第二个动态下拉框应该仅根据所选省份显示正确的条目。

为此我已经建立了下面的代码：

的search.php

//$i is running up to the max amount of provinces 
//for each province there shall be one option in the html select 
//the session array provinceresults contains key1, key2, province (english), province (other language) 
for($i=0; $i < $countProvinces; $i++) { 

    echo "<option value=".$_SESSION['provincesresults'][$i][0]." onClick=\"removeSelected(\".$i.\")\">".$_SESSION['provincesresults'][$i][1]."</option>"; 
} 

在search.php中我有应得到执行下面的JavaScript代码的主体部分时，我选择的一个每的onClick上述生成的选项：

<!--Javascript which is needed to call the dynamic_drop_down.php function per onClick event--> 
<script type=\"text/javascript\"> 
    function removeUnselected($key){ 
     document.getElementById(\"php_code\").innerHTML=\" 
     <?php 

      //Get all the values out of the district array out of pdo.vhd 
      $districtsSelected = removeUnselected(".$_SESSION['provincesresults'][$key][0]."); 
      } 
     ?>\"; 
    } 

所以我需要把第一个PHP部分的$ i计数器放到Javascript函数中。 之后，我需要在我的search.php

填充$ districtsSelected为进一步使用我的search.php PHP函数removeUnselected（“。$ _ SESSION ['provincesresults'] [$ key] [0]。”）;看起来是这样的，并包含在search.php中：

<?php 

/** 
*This php file is used to retrieve the districts for a selected province. 
*This file is called by search.php. 
*As input, the function needs to be called with the ID of the selected province, it will return all related districts. 
*/ 

function removeUnselected($provinceKey) { 

    //Build the array which returns the needed districts 
    $districtsSelected = array(); 

    //Loop through all the districts that have been read out of the database by get_value_help.php 
    for($i = 0; $i < count($_SESSION['districtsresults']); $i++) { 

     //Check if the province id out of the table dbo.vhp matches with the id out of the table dbo.vhd 
     if(strcmp($provinceKey, $_SESSION['districtsresults'][$i][1]) == 0) { 

     //Give back the district names in english if the language settings are english 
     if($_SESSION['lng'] == "english") { 

      //Remove any districts that were not selected 
      $districtsSelected[] = $_SESSION['districtsresults'][$i][2]; 
     } 
      //Give back the district names in khmer if the language settings are khmer 
     elseif ($_SESSION['lng'] == "khmer") { 

      //Remove any districts that were not selected 
      $districtsSelected[] = $_SESSION['districtsresults'][$i][3]; 
     } 
     } 
    } 

    //Return the result 
    return($districtsSelected); 
} 
?> 

我如何能在工作方式构建这个任何建议高度赞赏！

谢谢和问候，

codac

编辑： 我使用下面的JavaScript： http://www.mattkruse.com/javascript/dynamicoptionlist/index.html

我现在有两个问题： 由于有24个省，86个区， 1600个公社和13500个村庄，为下拉框创建需要几秒钟的时间。

的表格如下所示（省）：

country_id province_id province_en province_kh 
000000 010000   Banteay Mean Chey Khmer 1 
000000 020000   Bat Dambang Khmer 2 
000000 030000   Kampong Cham  Khmer 3 
000000 040000   Kampong Chhnang Khmer 

（区） province_id district_id district_en district_kh 010000 010200 Mongkol博瑞高棉1 010000 010300普农Srok高棉2 010000 010400柏威夏NETR柏威夏高棉3 010000 010500 Ou Chrov高棉4

...同样的公社和村庄。

我通过获取值了微软的SQL Server：

$sqlProvinces = "SELECT country_id, province_id, province_en, province_kh FROM dbo.vhp"; 
$sqlDistricts = "SELECT province_id, district_id, district_en, district_kh FROM dbo.vhd"; 

...同为乡镇和村庄。

就像在我的评论中提到，我存储在$ _SESSION这些值：

$_SESSION["provincesresults"]=$provincesResults; 
$_SESSION["districtsresults"]=$districtsResults; 

之后，我使用的功能“dyndrpdwn。PHP的 “生成下拉列表：

<?php 

function dyndrpdwn() { 

    //count the number of provinces, districts, communes and villages for the counters of the for-statements 
    $countProvinces = count($_SESSION["provincesresults"]); 
    $countDistricts = count($_SESSION["districtsresults"]); 
    $countCommunes = count($_SESSION["communesresults"]); 
    $countVillages = count($_SESSION["villagesresults"]); 

    //NULL the return values 
    $returnPD = NULL; 
    $returnC = NULL; 
    $returnV = NULL; 
    $defaultP = NULL; 
    $defaultD = NULL; 
    $defaultC = NULL; 
    $defaultV = NULL; 

    //Set start value for the counters to 0 
    $j = 0; 
    $k = 0; 
    $l = 0; 

    //Start the JavaScript and create the DynamitOptionList 
    $returnPD = "<script type=\"text/javascript\"> 
        var makeGeo = new DynamicOptionList(\"provinces\",\"districts\",\"communes\",\"villages\");"; 

    //Loop through all Provinces 
    for($i = 0; $i < $countProvinces; $i++) { 

     //Create the optionlist for provinces 
     $returnPD = $returnPD."makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").addOptionsTextValue("; 

     //Create the optionlist for districts ("while" if more performant than "for"!) and make sure that counter is not getting out of index 
     while($j < $countDistricts && $_SESSION["provincesresults"][$i][1] == $_SESSION["districtsresults"][$j][0]) { 

     $returnPD = $returnPD."\"".$_SESSION["districtsresults"][$j][2]."\",\"".$_SESSION["districtsresults"][$j][1]."\","; 

     $returnC = $returnC."makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").forValue(\"".$_SESSION["districtsresults"][$j][1]."\").addOptionsTextValue("; 

     //Create the optionlist for communes ("while" if more performant than "for"!) and make sure that counter is not getting out of index 
     while($k < $countCommunes && $_SESSION["districtsresults"][$j][1] == $_SESSION["communesresults"][$k][0]) { 

      $returnC = $returnC."\"".$_SESSION["communesresults"][$k][2]."\",\"".$_SESSION["communesresults"][$k][1]."\","; 

      $returnV = $returnV."makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").forValue(\"".$_SESSION["districtsresults"][$j][1]."\").forValue(\"".$_SESSION["communesresults"][$k][1]."\").addOptionsTextValue("; 

      //Create the optionlist for villages ("while" if more performant than "for"!) and make sure that counter is not getting out of index 
      while($l < $countVillages && $_SESSION["communesresults"][$k][1] == $_SESSION["villagesresults"][$l][0]) { 

       $returnV = $returnV."\"".$_SESSION["villagesresults"][$l][2]."\",\"".$_SESSION["villagesresults"][$l][1]."\","; 

       //Set the Default Value 
      $defaultV = "makeGeo.forValue(\"".$_SESSION["communesresults"][$k][1]."\").setDefaultOptions(\"".$_SESSION["searchresultspmd"][0][8]."\");"; 

       //Increase the counter by 1 
       $l++; 
      } 

      //Cut the last "," of the string after the last value of $returnC 
      $returnV = substr($returnV, 0, -1); 

      //Close the JavaScript statement 
      $returnV = $returnV.");"; 

      //If there is no village for the commune, remove the already prepared string "makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").forValue(\"".$_SESSION["districtsresults"][$j][1]."\").forValue(\"".$_SESSION["communesresults"][$k][1]."\").addOptionsTextValue(" 
      if(substr($returnV,-21) == "addOptionsTextValue);") { 

       $returnV = substr($returnV, 0, -86); 
      } 

      //Set the Default Value 
      $defaultC = "makeGeo.forValue(\"".$_SESSION["districtsresults"][$j][1]."\").setDefaultOptions(\"".$_SESSION["searchresultspmd"][0][7]."\");"; 

      //Increase the counter by 1 
      $k++; 
     } 

     //Cut the last "," of the string after the last value of $returnC 
     $returnC = substr($returnC, 0, -1); 

     //Close the JavaScript statement 
     $returnC = $returnC.");"; 

     //If there is no commune for the district, remove the already prepared string "makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").forValue(\"".$_SESSION["districtsresults"][$j][1]."\").addOptionsTextValue(" 
     if(substr($returnC,-21) == "addOptionsTextValue);") { 

      $returnC = substr($returnC, 0, -66); 
     } 

     //Set the Default Value 
     $defaultD = "makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").setDefaultOptions(\"".$_SESSION["searchresultspmd"][0][8]."\");"; 

     //Increase the counter by 1 
     $j++; 
     } 

     //Cut the last "," of the string after the last value of $returnPD 
     $returnPD = substr($returnPD, 0, -1); 

     //Close the JavaScript statement 
     $returnPD = $returnPD.");"; 

     //If there is no district for the province, remove the already prepared string "makeGeo.forValue(\"".$_SESSION["provincesresults"][$i][1]."\").addOptionsTextValue(" 
     if(substr($returnPD,-21) == "addOptionsTextValue);") { 

     $returnPD = substr($returnPD, 0, -47); 
     } 

     //Set the Default Value 
     $defaultP = "makeGeo.forValue(\"provinces\").setDefaultOptions(\"".$_SESSION["provincesresults"][$i][1]."\");"; 
    }    

    //Put Provinces, Districts, Communes and Villages together and close the Javascript 
    $returnPDCV = $returnPD.$returnC.$returnV.$defaultD.$defaultC.$defaultV."</script>"; 

    //Return the result 
    return sprintf($returnPDCV); 
} 
?> 

为了使用JavaScript，我用在patient_update.php下面的代码：

//include the dynamic drop down generator 
include("/functions/dyndrpdwn.php"); 

<!--Adding JavaScript for dynamic dropdown list--> 
<script type=\"text/javascript\" src=\"/js/dynamicoptionlist.js\"></script> 

//Call the dynamic drop down function 
echo dyndrpdwn(); 

echo"<!--Province Create Drop-Down Field--> 
    <select name=\"provinces\" class =\"dropdown\">"; 

//Fill the drop down, when data is received by get_value_help.php or if session array is already filled 
if(isset($_GET["value"]) == "true" && $_GET["value"] == "receive" || isset($_SESSION["provincesresults"]) == "true" && count($_SESSION["provincesresults"]) > 0) { 

    //Get all the values out of the Province array out of pdo.vhd 

$ countProvinces =计数（$ _ SESSION [” provincesresults“]）;

for($i=0; $i < $countProvinces; $i++) { 

     //Display the Khmer or the English language depending on the website settings. $_SESSION["searchresultspmd"][0][5]) = province_id in dbo.pmd 
     //$_SESSION["provincesresults"][$i][1] = province_id in dbo.vhp 
     if(isset($_SESSION["lng"]) == "true") { 

     switch ($_SESSION["lng"]) { 

      case "english": 

       if($_SESSION["provincesresults"][$i][2] == $_SESSION["searchresultspmd"][0][5]) { 

        echo"<option value=".$_SESSION["provincesresults"][$i][1]." SELECTED>"; 
       } 
       else { 

        echo"<option value=".$_SESSION["provincesresults"][$i][1].">"; 
       } 

       echo"".$_SESSION["provincesresults"][$i][2]." 
        </option>"; 
       break; 

      case "khmer": 

       if($_SESSION["provincesresults"][$i][2] == $_SESSION["searchresultspmd"][0][5]) { 

        echo"<option value=".$_SESSION["provincesresults"][$i][1]." SELECTED>"; 
       } 
       else { 

        echo"<option value=".$_SESSION["provincesresults"][$i][1].">"; 
       } 

       echo"".$_SESSION["provincesresults"][$i][3]." 
        </option>"; 
       break; 
     } 
     } 
    } 
} 

echo"   </select> 
      </td> 
      <td> 

       <!--District Create Drop-Down Field--> 
       <select name=\"districts\" class =\"dropdown\"> 
        <script type=\"text/javascript\"> 
        makeGeo.printOptions(\"districts\") 
        </script> 
       </select> 
      </td> 
      <td> 

       <!--Commune Create Drop-Down Field--> 
       <select name=\"communes\" class =\"dropdown\"> 
        <script type=\"text/javascript\"> 
        makeGeo.printOptions(\"communes\") 
        </script> 
       </select> 
      </td> 
      <td> 

       <!--Village Create Drop-Down Field--> 
       <select name=\"villages\" class =\"dropdown\"> 
        <script type=\"text/javascript\"> 
        makeGeo.printOptions(\"villages\") 
        </script> 
       </select> 
      </td> 

...

因此，有两个问题，现在：

1. 调用dyndrpdwn.php函数需要几秒钟的时间，因为有〜24个省，〜86个区，〜1600个社区和〜13500个村庄和我循环它们。有没有办法改善性能？
2. With setDefaultOptions我尝试为正确的下拉列表设置默认值。但在我的代码中不起作用。我将它与[JavaScript网站] [1]上的示例进行了比较，但是我找不到错误...您能否看到它为什么不能像我这样做？

结果目前看起来像这样：

<script type="text/javascript"> 
var makeGeo = new DynamicOptionList("provinces","districts","communes","villages"); 

这将创建一个省份和地区的条目：

makeGeo.forValue("010000").addOptionsTextValue("Mongkol Borei","010200","Phnum Srok","010300","Preah Netr Preah","010400","Ou Chrov","010500","Serei Saophoan","010600","Thma Puok","010700","Svay Chek","010800","Malai","010900"); 

这对公社创建条目

makeGeo.forValue("010000").forValue("010200").addOptionsTextValue("Banteay Neang","010201","Bat Trang","010202","Chamnaom","010203","Kouk Ballangk","010204","Koy Maeng","010205","Ou Prasat","010206","Phnum Touch","010207","Rohat Tuek","010208","Ruessei Kraok","010209","Sambuor","010210","Soea","010211","Srah Reang","010212","Ta Lam","010213"); 

这创建了村庄的条目：

makeGeo.forValue("010000").forValue("010200").forValue("010201").addOptionsTextValue("Ou Thum","01020101","Phnum","01020102","Banteay Neang","01020103","Kouk Pnov","01020104","Trang","01020105","Pongro","01020106","Kouk Tonloab","01020107","Trabaek","01020108","Khile","01020109","Samraong Pen","01020110","Dang Run Lech","01020111","Dang Run Kaeut","01020112","Ou Snguot","01020113","Prey Changha Lech","01020114","Prey Changha Kaeut","01020115","Ou Andoung Lech","01020116","Ou Andoung Kandal","01020117","Ou Andoung Kaeut","01020118","Kouk Kduoch","01020119"); 

而这应该设置省，区和公社的默认值（只有3个例子;他们没有工作至今...）：

makeGeo.forValue("240000").setDefaultOptions("Boeng Trakuon"); 
makeGeo.forValue("240200").setDefaultOptions("Ou Andoung"); 
makeGeo.forValue("240204").setDefaultOptions("Boeng Trakuon");</script> 

<!--Province Create Drop-Down Field--> 
<select name="provinces" class ="dropdown"> 
    <option value=010000>Banteay Mean Chey 
    </option><option value=020000>Bat Dambang 
    </option><option value=030000>Kampong Cham 
    </option><option value=040000>Kampong Chhnang 
    </option><option value=050000>Kampong Spueu 
    </option><option value=060000>Kampong Thum 
    </option><option value=070000>Kampot 
    </option><option value=080000>Kandal 
    </option><option value=090000>Kaoh Kong 
    </option><option value=100000>Kracheh 
    </option><option value=110000>Mondol Kiri 
    </option><option value=120000>Phnom Penh 
    </option><option value=130000>Preah Vihear 
    </option><option value=140000>Prey Veaeng 
    </option><option value=150000>Pousat 
    </option><option value=160000>Rotanak Kiri 
    </option><option value=170000>Siem Reab 
    </option><option value=180000>Krong Preah Sihanouk 
    </option><option value=190000>Stueng Traeng 
    </option><option value=200000>Svay Rieng 
    </option><option value=210000>Takaev 
    </option><option value=220000>Otdar Mean Chey 
    </option><option value=230000>Krong Kaeb 
    </option><option value=240000 SELECTED>Krong Pailin 
    </option></select> 

    </td> 
    <td> 

     <!--District Create Drop-Down Field--> 
     <select name="districts" class ="dropdown"> 
     <script type="text/javascript"> 
      makeGeo.printOptions("districts") 
     </script> 
     </select> 
    </td> 
    <td> 

     <!--Commune Create Drop-Down Field--> 
     <select name="communes" class ="dropdown"> 
     <script type="text/javascript"> 
      makeGeo.printOptions("communes") 
     </script> 
     </select> 
    </td> 
    <td> 

     <!--Village Create Drop-Down Field--> 
     <select name="villages" class ="dropdown"> 
     <script type="text/javascript"> 
      makeGeo.printOptions("villages") 
     </script> 
     </select> 
    </td> 

我知道它的相当多的东西，通过看，对不起那个butevery帮助高度赞赏！

Answer 1

不幸的是，上面概述的方法不起作用。当你在一个javascript段中使用php时，你必须记住，只有当从服务器请求包含javascript的文件时才会评估php代码。 PHP代码在请求期间输出的任何内容（例如，通过'echo'命令）将成为您的javascript函数的一部分。在上面的情况下，你没有输出任何东西，所以一旦页面加载，你的javascript代码基本上会读取.innerHTML=\" \";。即使你在那里输出数据，它也不会是动态的。

在我看来，你有3种选择：

1. 使用AJAX来加载从一个PHP文件中的第二个下拉的HTML。如果你已经熟悉AJAX，这绝对是一种方式，否则可能会有点棘手。如果你不熟悉，我肯定会建议在尝试实现这个选项之前通过几个教程。

2. 当用户更改第一个下拉列表时重新载入页面，并使用查询字符串参数告诉您的PHP脚本选择了哪个省份。这可能不是一个很好的选择，特别是如果这对下拉菜单是用户可能已经输入了一些数据的更大形式的一部分。

3. 让您的PHP输出第一个下拉菜单的HTML，然后单独列出每个省的下拉菜单，列出各自的区域。 （因此，如果你有10个省份，总共可以创建11个下拉菜单。）然后，您将使用CSS样式display: none;来隐藏辅助下拉菜单，并使用javascript将其样式切换为display: inline-block;。此选项不适用于大量选项，因为您正在加载大量可能不必要的数据。

出于好奇，为什么要将省数据存储在用户的$_SESSION变量中？我通常会尝试为用户特定的数据或有关接口状态的信息进行预留。