Populating dropdown - PHP Ajax MySQL

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一整个雨季
一整个雨季 2020-12-10 23:21

I have 2 dropdowns on my HTML page : The first drop down contains the database column names based on which the the second dropdown would be populated i.e.

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  • 2020-12-10 23:43

    You can use ajax for this purpose

    eg1.html

        <html>
        <head><title></title>
        </head>
        <body>
        <form method="POST" action="" name="mainForm">
        <table>
            <tr>
                <td> Filter by: </td>
                <td>
                    <div id="first">
                       <select id="first_dropdown">
                          <option value="All">All</option>
                          <option value="Degree">Degree</option>
                          <option value="City">City</option>
                       </select>
                </td>
             </tr>
             <tr>
                <td>&nbsp</td>
                <td>
                   <div id="second">
                      <select id="second_dropdown">
    
                      </select>
                   </div>
                </td>
             </tr>
          </table>
       </form>
    </body>
    </html>
    
        <script src = "https://code.jquery.com/jquery-3.1.0.min.js"></script>
        <script type="text/javascript">
        $(document).ready(function(){
            $('#first_dropdown').change(function(){
                $.ajax({
                    'type' : 'post',
                    'url' : 'getDropdownOptions.php',
                    'data': 'first=' + $(this).val(),
                    'success' : function(data) {
                        $('#second_dropdown').html(data);
                    }
                 });
              });
            });
        </script>
    

    getDropdownOptions.php

        <?php
    
        $link = mysql_connect("localhost", "root", "");
    
        if (!$link) {
            die('Could not connect: ' . mysql_error());
        }
        if (mysql_select_db("myDatabase", $link)) {
            $first = mysql_real_escape_string($_REQUEST["first"]);
            $query = "SELECT " . $first . " FROM myTable GROUP BY " . $first;
            $data  = mysql_query($query);
    
            $rtn_data = '';
            while ($row = mysql_fetch_row($data)) {
                $rtn_data .= "<option value=\"" . $row[0] . "\">" . $row[0] . "        </option>";
            }
            echo $rtn_data;
            exit;
        }
        echo mysql_error();
    
        ?>
    
    0 讨论(0)
  • 2020-12-10 23:43
    Divyesh here, your answer is
    ==============================
    edit.php
    ==============================
    <!-- edit.php -->
    <?php
    include("config.php");
    $id=$_REQUEST['id'];
    echo $id;
    $query=mysqli_query($con,"SELECT * FROM register r
    INNER JOIN country c ON r.cuid = c.cuid
    INNER JOIN state s ON r.sid = s.sid
    INNER JOIN city ct ON r.cid = ct.cid where id='$id'");
    
    while($r=mysqli_fetch_array($query))
    {
    
         $fn=$r['firstname'];
         $add=$r['address'];
         $gn=$r['gender'];
         $hobby=$r['hobby'];
         $h=explode(',',$hobby);
         $q=array('reading','traveling','cricket','drawing');
         $country=$r['cuid'];
         $state=$r['sid'];
         $city=$r['cid'];
         echo $gn;
         $edu= $r['education'];
         $email=$r['email'];
         $pass=$r['password'];
         $conpass=$r['conpassword'];
         $phno=$r['phoneno'];
    }
    
    ?>
    <html>
    <head>
        <script src="jquery.js"></script>
    <script type="text/javascript">
    $(document).ready(function(){
    
        $('#country').on('change',function(){
            var countryID = $(this).val();
            if(countryID){
                $.ajax({
                    type:'POST',
                    url:'ajaxData.php',
                    data:'cuid='+countryID,
                    success:function(html){
                        $('#state').html(html);
                        $('#city').html(html); 
                    }
                }); 
            }else{
                $('#state').html(html);
                $('#city').html(html); 
            }
        });
    
        $('#state').on('change',function(){
            var stateID = $(this).val();
            if(stateID){
                $.ajax({
                    type:'POST',
                    url:'ajaxData.php',
                    data:'sid='+stateID,
                    success:function(html){
                        $('#city').html(html);
                    }
                }); 
            }else{
                $('#city').html(html); 
            }
        });
    });
    </script>
    </head>
        <body>
            <form method="post" action="update.php">
                <table border="1" align="center">
                <caption>Edit user data</caption>
                <tr>
                    <td>First name</td>
                    <td><input type="text" name="fn" value="<?php echo $fn;?>"></td>
                </tr>
                <tr>
                    <td>Address</td>
                    <td><input type="text" name="add" value="<?php echo $add;?>"></td>
                </tr>
                <tr>
                    <td>Gender</td>
                    <td><input type="radio" name="gn" value="male" <?php echo ($gn=='male')?'checked':'' ; ?> size="17">Male
                    <input type="radio" name="gn" value="female" <?php echo ($gn=='female')?'checked':'' ; ?> size="17">Female
                    </td>
                </tr>
                <tr>
                    <td>Hobby</td>
                    <td><input type="checkbox" name="hobby[]" value="reading" <?php if(in_array('reading',$h)){echo ("checked:'checked'");}?> >reading
                    <input type="checkbox" name="hobby[]" value="traveling" <?php if(in_array('traveling',$h)){echo ("checked:'checked'");}?> >traveling
                    <input type="checkbox" name="hobby[]" value="cricket" <?php if(in_array('cricket',$h)){echo ("checked:'checked'");}?> >cricket
                    <input type="checkbox" name="hobby[]" value="drawing" <?php if(in_array('drawing',$h)){echo ("checked:'checked'");}?> >drawing</td>
                </tr>
                <?php
                $query = mysqli_query($con,"SELECT * FROM country");
    
                //Count total number of rows
                $rowCount = mysqli_num_rows($query);
                ?>
                <td>Country</td>
                <td><select name="country" id="country">
                    <option value="<?php echo $country;?>"><?php echo $country;?></option>
                    <?php
                    if($rowCount > 0)
                    {
                        while($row = mysqli_fetch_array($query))
                        { 
                            echo '<option value="'.$row['cuid'].'">'.$row['country'].'</option>';
                        }
                    }
                    else
                    {
                        echo '<option value="">Country not available</option>';
                    }
                    ?>
                </select>
                </td></tr>
                <tr>
                <td>State</td>
                <td>
                <select name="state" id="state">
                    <option value="<?php echo $state;?>"><?php echo $state;?></option>
    
                </select>
                </td></tr>
                <tr>
                <td>City</td>
                <td>
                <select name="city" id="city">
                    <option value="<?php echo $city;?>"><?php echo $city;?></option>
    
                </select>
                </td>
                </tr>
                <tr>
                    <td>Education</td>
                    <td><input type="text" name="edu" value="<?php echo $edu;?>"></td>
                </tr>
                    <td>Email</td>
                    <td><input type="text" name="email" value="<?php echo $email;?>"></td>
                </tr>
                <tr>
                    <td>Password</td>
                    <td><input type="text" name="pass" value="<?php echo $pass;?>"></td>
                </tr>
                <tr>
                    <td>Confirm password</td>
                    <td><input type="text" name="conpass" value="<?php echo $conpass;?>"></td>
                </tr>
                <tr>
                    <td>Phone no</td>
                    <td><input type="text" name="phno" value="<?php echo $phno;?>"></td>
                </tr>
                <tr>
                    <td><input type="hidden" name="id" value="<?php echo $id;?>">
                    <input type="submit" name="update" value="update"></td>
                </tr>
                </table>
            </form>
        </body>
    </html>
    
    ================
    <h3>ajaxData.php</h3>
    ================
    <!--ajaxData.php-->
    <?php
    //Include database configuration file
    include("config.php");
    
    if(isset($_POST["cuid"]) && !empty($_POST["cuid"]))
    {
        //Get all state data
        $query = mysqli_query($con,"SELECT * FROM state WHERE cuid = ".$_POST['cuid']."");
    
        //Count total number of rows
        $rowCount = mysqli_num_rows($query);
    
        //Display states list
        if($rowCount > 0)
        {
            echo '<option value="">Select state</option>';
            while($row =  mysqli_fetch_array($query))
            { 
                echo '<option value="'.$row['sid'].'">'.$row['state'].'</option>';
            }
        }
        else
        {
            echo '<option value="">State not available</option>';
        }
    }
    
    if(isset($_POST["sid"]) && !empty($_POST["sid"]))
    {
        //Get all city data
        $query = mysqli_query($con,"SELECT * FROM city WHERE sid =".$_POST['sid']."");
    
        //Count total number of rows
        $rowCount = mysqli_num_rows($query);
    
        //Display cities list
        if($rowCount > 0)
        {
            echo '<option value="">Select city</option>';
            while($row = mysqli_fetch_array($query))
            { 
                echo '<option value="'.$row['cid'].'">'.$row['city'].'</option>';
            }
        }
        else
        {
            echo '<option value="">City not available</option>';
        }
    }
    ?>
    
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  • 2020-12-11 00:01

    If you want a more dynamic solution (that will accommodate changes to the background DB) you can do something like this on your page:

    <script>
            function changeSecond(first){
            var xmlhttp;
            if (window.XMLHttpRequest)
              {// code for IE7+, Firefox, Chrome, Opera, Safari
              xmlhttp=new XMLHttpRequest();
              }
            else
              {// code for IE6, IE5
              xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
              }
            xmlhttp.onreadystatechange=function()
            {
              if (xmlhttp.readyState==4 && xmlhttp.status==200)
                {
                var res=xmlhttp.responseText;
                document.getElementById("second").innerHTML=res;
                }
              }
            xmlhttp.open("GET","second_script.php?first="+first,true);
            xmlhttp.send();
            }
            </script>
    ...
    <select onChange="changeSecond(this.value)">
    <option value="Degree">Degree</option>
    <option value="City">City</option>
    </select>
    <div id="second"><select><option value=""></option></select></div>
    

    and then a script similar to:

    <?php
    //database connection
    $first=mysql_real_escape_string($_REQUEST["first"]);
    $query="SELECT ".$first." FROM tablename GROUP BY ".$first;
    $data=mysql_query($query);
    echo "<select>";
    while($row=mysql_fetch_row($data)){
    echo "<option value=\"".$row[0]."\">".$row[0]."</option>";
    }
    echo "</select>";
    ?>
    

    I guess for real flexibility you'd also want to dynamically populate that first one using mysql_field_name in another script similar to above

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  • 2020-12-11 00:04

    You could either have all the dropdown needed preloaded and hidden, and show them when the 'change' event is triggered in the first dropdown, or have two dropdowns and empty it on that same 'change' event.

    If you choose the second approach you should buffer the data to insert in the dropdown list, partially or totally

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  • 2020-12-11 00:07

    code for the main file in which you want to populate drop down based on other in below example i show localities in child dropdown for that city that is selected in parent drop down

        <script type="text/javascript">
        function city_locality(val)
        {
        // alert (val);
        url="<?php echo $this->baseurl ?>/components/com_ezportal/includes/query.php";
        data="stid="+val;
    $.post(url,data,function(data){
    $("#locid").html(data);
    });     
        }
        </script>
        <select name="filter_1state" id="filter_1state" onChange="city_locality(this.value)">
          <option value="0">-- Select City --</option>
          <option value="1">Lahore</option>
          <option value="2">Karachi</option>
          <option value="3">Islamabad</option>
          <option value="4">Quetta</option>
          <option value="5">Multan</option>
        </select>
    

    code for the file query.php

        <?php 
        $link = mysql_connect('localhost', 'root', '');
        mysql_select_db('mydatabase');
        if (isset($_POST['stid']))
        {
            $stid = $_POST['stid'];
            $query= mysql_query("SELECT id,ezcity FROM tbl_locality WHERE stateid = '".$stid."' GROUP BY ezcity"); 
        ?>
            <option value="0">-- Select Locality --</option>
        <?php
            while($row = mysql_fetch_array($query))
            {
        ?>
            <option value="<?php echo $row['id']?>"><?php echo $row['ezcity']?>        </option> 
            <?php
            }
        }
        ?>
    
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