AJAX chained select

~s.o.s~ · 2008-08-22T13:10:22+00:00

How about showing what you have attempted so far?

trevata 0 Newbie Poster · 2008-08-22T15:04:45+00:00

Ok this is the drop down for the city:

<div class="titBox titBoxM"><span class="fontF1 fontWBold fontSzBig"><?=$lang['grad']?>:</span></div>
    <div class="boxGrad boxGradM">
    <center>
    <?=addDropDown(0,0,0,"gradove",$gradove[$dropN],$lang['emptyDropDown'],'class="szMT2"',$lang['raion'],1,"\n","\n",""); ?>
    </center>
    </div>

The dropdown looks like this

<select name="city">
<option value="0">City 1</option>
<option value="1">City 2</option>
<option value="2">City 3</option>
etc.
</select>

This is how i get the array with neighborhoods:

<div class="titBox titBoxM"><span class="fontF1 fontWBold fontSzBig"><?=$lang['kvartala']?>:</span></div>
    <div class="boxSelect">
    <?
    for ($i=0;$i<sizeof($lang['kvartalS']);$i++){
    echo '<input type="checkbox" name="kvartal" value="'.$i.'" /> <span class="fontF1 fontSzBig">'.$lang['kvartalS'][$i].'</span><br />'."\n".' ';
    }
    ?>
    </div>

~s.o.s~ · 2008-08-22T15:47:48+00:00

I don't know PHP so I won't be making any erroneous assumptions here but achieving this depends on how you are pulling the data irrespective of the server side language used. Are you pulling the *entire* data in a single request and toggling the SELECT boxes using Javascript or are you fetching the neighborhood data *on demand*.

No matter the approach, it should be pretty easy if you pass the data from PHP to Javscript in JSON format. Here is a pure Javascript implementation which should push you in the right direction.

<!--
    Dynamic drop downs using Javascript
    Copyright (C) 2008  sos aka Sanjay

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
            "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Select Example</title>
    <script type="text/javascript">
    function fillSelBox(srcElem, destName) {
      var selOne = srcElem;
      var frm = srcElem.form;
      var selTwo = frm.elements[destName];
      var map = 
      {"fruit": 
        {"default": "- Select -", mango: "Mango", custardApple: "Custard Apple"},
       "vegetable": 
        {"default": "- Select -", bitterGourd: "Bitter Gourd", onion: "Onion"},
       "fastFood":
        {"default": "- Select -", noodle: "Noodles", soup: "Soup"},
       "default":
        {"default": "- Select -"}
      };
      selBoxUtil(selOne, selTwo, map);
    }
    
    function selBoxUtil(src, dest, map) {
      if(!src || !dest || !map) {
        return;
      }
      removeAll(dest);
      var selected = src.options[src.selectedIndex].value;
      for(var key in map) {
        if(key == selected) {
          var valueMap = map[key];
          for(var innerKey in valueMap) {
            var val = valueMap[innerKey];
            addOption(dest, val, innerKey);
          }          
        }
      }
    }
    
    function addOption(e, value, label) {
      if(!e) {
        return;
      }
      var o = new Option(value, label);
      try {
        e.add(o);
      } catch(ee) {
        e.add(o, null);
      }
    }
    
    function removeAll(e) {
      if(e && e.options) {
        e.options.length = 0;
      }
    }
    </script>
</head>
<body id="bdy">
  <form id="frm" action="#">
  <div id="container">
    <select name="selOne" id="selOne" onchange="fillSelBox(this, 'selTwo');">
      <option value="default">- Select -</option>
      <option value="fruit">Fruits</option>
      <option value="vegetable">Vegetables</option>
      <option value="fastFood">Fast Food</option>
    </select>
    <select name="selTwo" id="selTwo">
      <option value="default">- Select -</option>
    </select>
  </div>
  </form>
</body>
</html>

Again as to how this is achieved using PHP would be best posted in the PHP forums.

trevata 0 Newbie Poster · 2008-08-22T16:09:12+00:00

No no man, can AJAX send two variables to the PHP, one with the starting number and second with the finishing number....
Something like this if City 1 is selected the script sends var1=0 and var2=89, or if City 2 is selected the script sends var1=90 and var2=110 so the php script can get these two variables and get the neighborhoods from the array and display them :)

~s.o.s~ · 2008-08-22T16:35:42+00:00

Yes, you can send more than one variables to your PHP script residing on the server. Just append the start and end points as request parameters to the query string which you would be using to make an Ajax request. Something like /php/process.php/?start=0&end=10 . Also make sure you encode the URL before making an Ajax request for proper encoding of special characters (like space for instance). And in process.php, you can retrieve the variables from the request object. In J2EE, it would be something like request.getParameter("start") .

Assuming this isn't your first stint with Ajax, you can easily process the response using either the responseText or responseXML attribute of XMLHttpRequest object.

trevata 0 Newbie Poster · 2008-08-22T18:25:54+00:00

Thanks man.... I think i can do that.. If I need help I'll write here. Thanks again :)