How to add select box field dynamically after clicking add button by using php or javascript and store selected value in selected box in database

Question

if (isset($_POST['dept']) && isset($_POST['batch']) && isset($_POST['Month']) && isset($_POST['Year']) && isset($_POST['semester']))   // based on these values selected from database 
{
$dept = $_POST['dept'];
$batch = $_POST['batch'];
 $month = $_POST['Month'];
$year = $_POST['Year'];
 $semester = $_POST['semester'];

$query = db_select('student_master');
$query->fields('student_master', array('reg_no','name','dob','dept_code','degree','batch_year'));
$query->condition('dept_code',$dept,'=') AND $query->condition('batch_year',$batch,'=');
$results = $query->execute();

echo "<table>";
echo "<tr>";
echo "<td><label for='reg_no'> Registration Number </label></td>";
echo "<td>";
echo "<select name='reg_no'>";

foreach($results as $student_result)
{ 
echo "<option value ='$student_result->reg_no'> $student_result->reg_no</option>";
} 

echo "</select>";
echo "</td>";
echo "</tr>";

$query = db_select('subject');
$query->fields('subject', array('subject_name','credits','subject_code'));
$query->condition('dept_code',$dept,'=') AND $query->condition('semester_appear',$semester,'=') ;
$subject_results = $query->execute();

echo "<tr>";
echo "<td><label for='Subject'>Subject Name</label></td>";  
echo "<td>";
echo "<select name = 'sub_name' id = 'sub_name'>";

foreach($subject_results as $subjects_result)
{ 
echo "<option value ='$subjects_result->subject_code'> $subjects_result->subject_name</option>";
} 

echo "</select>";
echo "</td>";
echo "</tr>";

echo "<tr>";
echo "<td><label for='Subject'>Subject Serial Number</label></td>";
echo "<td>";
echo "<select name='subject_serial' id = 'sub_name'>";

if ($semester == "SEMESTER-I")
{
for($i=101; $i<=110; $i++ )
{ 
echo "<option value ='$i'>$i</option>";

} 
}
elseif ($semester == "SEMESTER-II")
{
for($i=201; $i<=210; $i++ )
{ 
echo "<option value ='$i'>$i</option>";
} 
}

elseif ($semester == "SEMESTER-III")
{
for($i=301; $i<=310; $i++ )
{ 
echo "<option value ='$i'>$i</option>";
} 
}
elseif ($semester == "SEMESTER-IV")
{
for($i=401; $i<=410; $i++ )
{ 
echo "<option value ='$i'>$i</option>";
} 
}

echo "</select>" ;
echo "</td>";
echo "</tr>";
echo "</table>";

}
else
{
return "please check the your input";
}

How to add select box field dynamically after clicking add button (the selected box contain the datas from database after clicking the add button, and same selected value store in database) by using php or javascript and store selected value in selected box to database

Answer 1

Create a PHP page that returns the required HTML string only

And then on client side using jquery you can append that html to desired element

eg

$("#btnAddnew").click(function(){
   $.get('ajax/test.php?id=1', function(data) {
       $('#divDropdown').html(data);
   });
});

Then in post you can pass the selected dropdown's value using javascript

eg If it is like

then $("#drpRegNum").val() would give you the selected value