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best way to get form input names for dynamic dropdown?


man5
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Normally you can get input names from form using $_GET method.  However, with a multi level dropdown, the php query files are called externally and through the js code.

 

So I am wondering, what is the best way to get the input names of each dropdown? For eg. country, state, city.  Getting the input name for the country is easy; how would I get it for the state and city if they are in a seperate php files?  Do I get the input name in their own files and put them in a session?

Edited by man5
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I suppose I should be more clear.  Here is an example of a form dropdown.

<form action="" method="post" enctype="multipart/form-data >

	<div id="countrydiv">
		<select id="country" name="country" onChange="showRegion(this.value);">
		
			<option value="0">--Select Country--</option>
			
			<?php  
				// query to get the id and name of the country here.
			?>
		</select>
		
	</div>
	
	<div id="regiondiv">
		// this <select> option is in region.php that queries data from mysql table. It is called through js code in the head section of the website.
	</div>
		
	<div id="citydiv">
		// this <select> option is in city.php that queries data from mysql table. It is called through js code in the head section of the website.
	</div>
	<input type="submit" value="submit">
	
</form>	
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I'm sorry if I wasn't being clear. I have the dynamic ajax dropdown fully working.  I am just having hard to getting data from mysql table using the ajax dropdown.

 

For eg.

$country   =  $_GET['country'];
$region   =  $_GET['region'];
$city   =  $_GET['city'];


$stmt = $dbh->prepare("SELECT * FROM posts WHERE countryid = $country AND regionid= $region  AND cityid= $city ");

That's how the query looks like for getting the data from db.  The only problem with that is, $_GET region and city are not working. The data shows fine if i only use the country, because the country <select> is defined on the same page, while region and city <select> is defined on a sperate php page that is called with the ajax code.

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That is the wrong use of prepared queries. The variables $country, $region AND $city should be substituted by place holders. Then you use your DB class bind method to bind them to the placeholders

 

I dont know what DB class you're using but I'll link to PDO and MySQLi documentation for binding values to prepared queries

PDO::bind_param

MySQLi::bind_param

 

Also if your forms submit method is POST then you should retrive the form values from $_POST not $_GET

Edited by Ch0cu3r
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I think it's best if I show you my entire process. This should clear things up. I have the binding done in a db class so don't worry about that. Everything works, except fo the last bit where I would like to filter values from the db table based on the location of country,region,city.

 

Index.php

<html>
<head>  
    <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
    <script>
        function showRegion(str) {
            var xmlhttp;
            if (str.length==0) {
            document.getElementById("regiondiv").innerHTML="";
            return;
            }
            if (window.XMLHttpRequest) {
            xmlhttp=new XMLHttpRequest();
            }
            else {
            xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            xmlhttp.onreadystatechange=function() {
                if (xmlhttp.readyState==4 && xmlhttp.status==200) {
                document.getElementById("regiondiv").innerHTML=xmlhttp.responseText;
                }
            }
            xmlhttp.open("GET","showregion.php?country="+str,true);
            xmlhttp.send(null);
        }
        
        function showCity(str) {
            var xmlhttp;
            if (str.length==0) {
            document.getElementById("citydiv").innerHTML="";
            return;
            }
            if (window.XMLHttpRequest) {
            xmlhttp=new XMLHttpRequest();
            }
            else {
            xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            xmlhttp.onreadystatechange=function() {
                if (xmlhttp.readyState==4 && xmlhttp.status==200) {
                document.getElementById("citydiv").innerHTML=xmlhttp.responseText;
                }
            }
            xmlhttp.open("GET","showcity.php?region="+str,true);
            xmlhttp.send(null);
        }
    </script>
 </head>
<body>
<?php
    if(isset($_GET['submit']) {
    
        $country        =    $_GET['country'];
        $region2        =    $_GET['region'];
        $city2            =    $_GET['city'];
        
    
        
        $results = DB::getInstance()->query("SELECT * FROM posts WHERE countryId = {$country2}  AND regionId = {$region2} AND cityId = {$city2}");
        
        if(!$results) {

            echo 'Could not process!';
            
        } else if(!$results->count()) {
        
             echo 'No results found!';
            
        } else {
        
            foreach($results->results() as $row) {
                
                $date              =     $row->posted;
                $post_id          =     $row->post_id;
                $title             =     $row->title;
            
                echo $date;
                echo $post_id;
                echo $title;
            }
        }
    
    }
 ?>
    <form action="" method="get" enctype="multipart/form-data >
        select id="country" name="country" onChange="showHint(this.value);" required >

            <option value="0">--Select Country--</option>

            <?php  
                $getCountry = DB::getInstance()->query("SELECT * FROM countries");

                if(!$getCountry->count()) {

                    echo 'No Country found!';

                } else {

                    foreach($getCountry->results() as $row) {

                        $country_id     =   $row->countryId;
                        $country_name   =   $row->countryName;

                 ?><option value="<?php echo $country_id; ?>" ><?php echo $country_name; ?></option><?php

                    }
                }
            ?>


        </select>

        <div id="regiondiv">
        </div>
        
        <div id="citydiv">
        </div>
        
        <input type="submit" class="search" value="Search">
    </form>
</body>
</html>

showcity.php

$region_id   =  $_GET['region'];

$select_city = DB::getInstance()->get('cities', array('regionId', '=', $region_id));

if(!$select_city->count()) {

	echo 'No City found!';
	
} else {
	
?>
<select name="city" id="city" ><?php	

	?><option value=0" >---Select City---</option><?php
	
	foreach($select_city->results() as $row) {
	
		$city_id			=	$row->cityId;
		$city_name			=	$row->cityName;

	?><option value="<?php echo $city_id; ?>" ><?php echo $city_name; ?></option><?php

	}
	
?></select><?php		
}

showregion.php

$country_id  =  $_GET['country'];

$select_region = DB::getInstance()->get('regions', array('countryId', '=', $country_id));

if(!$select_region->count()) {

	echo 'No Region found!';
	
} else {

?>
<select name="region" id="region" onChange="showCity(this.value);"><?php	

	?><option value=0" >---Select Province/State---</option><?php
	
	foreach($select_region->results() as $row) {
	
		$region_id			=	 $row->regionId;
		$region_name		=	 $row->regionName;

	?><option value="<?php echo $region_id; ?>" ><?php echo $region_name; ?></option><?php

	}
	
?></select><?php		
}
Edited by man5
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