*solved* Dynamic Dropdowns using PHP - Tutorial/code ??

[swatisonee]

Hi

i remember seeing a tutorial or a code - cant remember which on creating a dynamic dropdowns using php (not js or ajax ).

I need something similar to selecting 1 country from a list of countries first and then the cities of the chosen country second and both choices being part of the same form.

If anyone can provide me a link to a tutorial / code , would be grateful. I've searched thru all that google came up for dynamic dropdowns using php and i cannot find what i need.


Thanks. Swati

[Orio]

That does need javascript.

Orio.

[taith]

since .php is only loaded once, you'd have to reload the page inbetween each selection... you'd probly want a to intermingle javascript and .php together to get something like this

[code]
<select size="1" onchange="document.location.href=this.value">
<option value="'.$PHP_SELF.'.?country='.$countryname.'">'.$countryname.'</option>
</select>

<?
switch($_GET[country]){
case "countryname":
 echo '<select size="1" onchange="document.location.href=this.value">';
 echo  '<option value="'.$PHP_SELF.'.?country='.$countryname.'">'.$countryname.'</option>';
 echo '</select>';
break;
}
?>
[/code]
or something to that effect...

[swatisonee]

JS is just not on - i'm looking at a total of some 5000 odd towns in the 2nd list. I realise using php means travelling back to the server but its still a better option.
Taith, i am veering towards using a combination of JS and PHP but since i dont know how to actually code it , i'd rather look at a done code and modify it or read some detailed tutorial on it... I did try my hand doing it with what i've read so far but since the script can run only when a value from an earlier form gets posted, its causing me a problem in where to run the js.

The bare bones of the php script is like this and the js/php needs to get inserted somewhere..any pointers ??

Thanks !

[code]<? include("protect.php"); ?>

<?php
$cid = $_GET["cid"];
echo $cid; // to confirm the value gets passed - it does


mysql_connect("localhost", $dbname, $dbpasswd )    or die ("Unable to connect to server.");

mysql_select_db($database)    or die ("Unable to select database.");


$sql1 = "SELECT * FROM `Customers` WHERE `CID`= $cid ";
$result1 = mysql_query($sql1);

$myrow1 = mysql_fetch_array($result1);

$company = $myrow1["Company"];
?>
<form enctype='multipart/form-data' action='add_custadd2.php?cid=<? echo $cid ?>&userid=<? echo $userid ?>' method='post'>
<table border="1" cellspacing="1" style="border-collapse: collapse" bordercolor="#000066" width="95%" cellpadding="5">


<tr><font face="Verdana" size="2">COMPANY</td>
    <input type=hidden name="company"  value="<? echo $company ?>">
    <input type=text name="company"  value="<? echo $company ?>" disabled="true">&nbsp;</td>

<tr>Country</td>
  <select name="ctid"><option value="">[Select One]
        <?php


  $result = mysql_query("SELECT * FROM `Countries`  ORDER BY `Country` asc ");

  if ($myrow = mysql_fetch_array($result)) {

    do {

       printf("<option value=%d>
        %s", $myrow["ctid"], $myrow["Country"]);

    } while ($myrow = mysql_fetch_array($result));

  echo "</select>\n";

  } else {

  echo "Sorry, no records were found!";

  }

  ?></td></tr>

  // JS-PHP needs to kick in at this point when selecting the 2nd dropdown
 
 
<tr>Towns</td>
  <select name="tid"><option value="">[Select One]
        <?php


  $resulta = mysql_query("SELECT * FROM `Towns`  WHERE `ctid` = $ctid ORDER BY `ctid` asc ");
  // This is the critical part where the value of country id is obtained to filter towns by country

  if ($myrowa = mysql_fetch_array($resulta)) {

    do {

       printf("<option value=%d>
        %s, %s", $myrowa["TID"], $myrowa["Town"], $myrowa["State"]);

    } while ($myrowa = mysql_fetch_array($resulta));

  echo "</select>\n";

  } else {

  echo "Sorry, no records were found!";

  }

  ?></td></tr>[/code]

[taith]

how about something like this?
[code]
<? include("protect.php");
$cid = $_GET["cid"];
echo $cid;

mysql_connect("localhost", $dbname, $dbpasswd ) or die ("Unable to connect to server.");

mysql_select_db($database) or die ("Unable to select database.");

$result1 = mysql_query("SELECT * FROM `Customers` WHERE `CID`= $cid ");
$myrow1 = mysql_fetch_array($result1);

$company = $myrow1["Company"];
?>
<form enctype='multipart/form-data' action='add_custadd2.php?cid=<?=$cid?>&userid=<?=$userid?>' method='post'>
<table border="1" cellspacing="1" style="border-collapse: collapse" bordercolor="#000066" width="95%" cellpadding="5">
  <tr><font face="Verdana" size="2">COMPANY
    <td><input type=hidden name="company"  value="<?=$company?>"><input type=text name="company"  value="<?=$company?>" disabled="true">&nbsp;</td>
    <tr>Country</td><select size="1" onchange="document.location.href=this.value"><option value="">[Select One]</option>
<?
$result = mysql_query("SELECT * FROM `Countries`  ORDER BY `Country` asc ");
while($myrow = mysql_fetch_array($result)){
if($row[country]==$_GET[country]) echo '<option selected value="?country='.$myrow[country].'">'.$myrow[country].'</option>';
else echo '<option value="?country='.$myrow[country].'">'.$myrow[country].'</option>';
}
echo '</select>';
?>
  </td>
</tr>
<?if(!empty($_GET[country])){?>
<tr>
  <td>Towns<br>
  <select name="tid"><option value="">[Select One]
        <?
$resulta = mysql_query("SELECT * FROM `Towns`  WHERE `ctid` = $ctid ORDER BY `ctid` asc ");
while($myrowa = mysql_fetch_array($resulta)){
echo '<option value=%d>%s, %s".', '.$myrowa["TID"].', '.$myrowa["Town"].','. $myrowa["State"];
}
echo "</select>\n";
?>
  </td>
</tr>
<?}?>
</table>
[/code]

[swatisonee]

I hate to do this - ask yet another question but i uploaded the code and while the 1st dropdown works, on selection , it loads again so the 2nd doesnt work at all. i turned error reporting on but cannot find a reason other than the fact that $ctid is not defined. $ctid is the value of field CTID(int) linked to Country(varchar) so if Norway is chosen and is listed at no. 24, $ctid = 24.


[code]$resulta = mysql_query("SELECT * FROM `Towns`  WHERE `ctid` = $ctid ORDER BY `ctid` asc ");[/code]

I tried defining it as under but then the whole page turns blank.

[code]else echo '<option value="?country='.$myrow[country].'">'.$myrow[country].'</option>';
}
echo '</select>';

$ctid = $myrow[ctid];
echo $ctid ; // doesnt echo out.
?>[/code]

Any guidance please ? Thanks !

[taith]

not a problem :-)  how about this modification?
[code]
<?
$result = mysql_query("SELECT * FROM `Countries`  ORDER BY `Country` asc ");
while($myrow = mysql_fetch_array($result)){
if($row[country]==$_GET[country]){
  $country=$myrow[country];
  echo '<option selected value="?country='.$myrow[country].'">'.$myrow[country].'</option>';
}else echo '<option value="?country='.$myrow[country].'">'.$myrow[country].'</option>';
}
echo '</select>';

echo $country;
?>
[/code]

[swatisonee]

Nope :-( . Still a blank page ....

[Barand]

AJAX is neater as it only refreshes the changed dropdown and not the whole page.

Example in my sig.

[swatisonee]

Hello Barand,

Thanks for the link- i had seen it and baaSelect when i first started doing this dropdown but  i've been making too many errors and havent been able to find their source. I modified _d and _o to use my data but if i am not mistaken _t is for a 3rd dropdown that i dont need.

I'm having a hard time understanding how it /ajax works . The way i understood it : Every destination is a function of origin, time and price . For my code, it means, every country is a function of city and its associated province .

Having chosen a destination(country), i have to choose an origin ( city ) and time (province) . But in my table structure of Towns, i have fields cityid(int), city(varchar), pid(int), province(varchar), ctid(int) , country(varchar).
That means function getTimes and function getPrice are not required. Which means i dont need to use the inner join in_t and if i dont, then how do i get the value of $id.

I also dont understand how the 4 php files are linked because i dont see any form processing in them just in the html file. Would i have to create a folder for the html , js and the 5 php files ?

Does that make sense ?

Thanks for reading this post !

[swatisonee]

With a lot of help got this to work in some fashion. its not neat and requires the whole page to reload but with no knowledge of ajax, its the best i can do for now. have posted the code in case anyone else would like to use it.

Anyway, Taith, Barand - thanks for stopping by to help

Swati