using davidstutz bootstrap-multiselect via PHP

multi_select.php

//more simply examples http://www.pipiscrew.com/2015/06/bootstrap-select-mutliselect/

////////////////////////[index.php]
<?php
//convert recordset to 1D array (will use it, to mark the multi-selects @ JS)
function get_array_by_set($db_set)
{
	$rec_children = array();
	foreach($db_set as $row) {
		$rec_children[]= $row[0];
	}

	return $rec_children;
}
	
///////////////////READ SPEFIC RECORD
if (isset($_GET["id"])) {
	$rec_id=intval($_GET["id"]);

	$row = getRow($db,"SELECT * FROM events where event_id=?",array($rec_id));
	
	//construct an array of children id records (fallback to JS)
	$key_topic_set = getSet($db, "select event_key_topic_id from event_key_topic_ties where event_id=?",array($rec_id));
 	$cmb_key_topic = get_array_by_set($key_topic_set);
 	
	//construct an array of children id records (fallback to JS)
	$present_set = getSet($db, "select event_present_id from event_present_ties where event_id=?",array($rec_id));
	$cmb_present = get_array_by_set($present_set);
	
	//construct an array of children id records (fallback to JS)
	$benefits_set = getSet($db, "select event_benefit_id from event_benefits_ties where event_id=?",array($rec_id));
	$cmb_benefits = get_array_by_set($benefits_set);

	//construct an array of children id records (fallback to JS)
	$reqs_set = getSet($db, "select event_requirement_id from event_requirement_ties where event_id=?",array($rec_id));
	$cmb_reqs = get_array_by_set($reqs_set);
	
	//construct an array of children id records (fallback to JS)
	$tauds_set = getSet($db, "select event_target_audience_id from event_target_audience_ties where event_id=?",array($rec_id));
	$cmb_tauds = get_array_by_set($tauds_set);
	
	//construct an array of children id records (fallback to JS)
	$sponsors_set = getSet($db, "select event_sponsor_id from event_sponsor_ties where event_id=?",array($rec_id));
	$cmb_sponsors = get_array_by_set($sponsors_set);
	
	//construct an array of children id records (fallback to JS)
	$speakers_set = getSet($db, "select event_speaker_id from event_speaker_ties where event_id=?",array($rec_id));
	$cmb_speakers = get_array_by_set($speakers_set);
	

}
///////////////////READ SPEFIC RECORD

//fill multi-selects 
$key_topics = getSet($db,"SELECT event_key_topic_id,event_key_topic_name FROM event_key_topics order by event_key_topic_name",null);

$presents = getSet($db,"SELECT event_present_id,event_present_name FROM event_presents order by event_present_name",null);

$benefits = getSet($db,"SELECT event_benefit_id, event_benefit_name FROM event_benefits order by event_benefit_name",null);

$reqs = getSet($db,"SELECT event_requirement_id, event_requirement_name FROM event_requirements order by event_requirement_name",null);

$target_audiences = getSet($db,"SELECT event_target_audience_id, event_target_audience_name FROM event_target_audiences order by event_target_audience_name",null);

$sponsors = getSet($db,"SELECT event_sponsor_id, event_sponsor_name FROM event_sponsors order by event_sponsor_name",null);

$speakers = getSet($db,"SELECT event_speaker_id, event_speaker_name FROM event_speakers order by event_speaker_name",null);
//fill multi-selects
?>

<script>

	//	jquery
	$(function() {
		///////////////////////////////////////////////////////////// FILL key_topics
		var jArray_key_topics =   <?php echo json_encode($key_topics); ?>;

		var combo_key_topics_rows = "";
		for (var i = 0; i < jArray_key_topics.length; i++)
		{
			combo_key_topics_rows += "<option value='" + jArray_key_topics[i]["event_key_topic_id"] + "'>" + jArray_key_topics[i]["event_key_topic_name"] + "</option>";
		}

		$("#cmb_key_topic").html(combo_key_topics_rows);
		
		$('#cmb_key_topic').multiselect({
		    includeSelectAllOption: true
		});

		///////////////////////////////////////////////////////////// FILL key_topics
		

		///////////////////////////////////////////////////////////// FILL presents (also included)
		var jArray_presents =   <?php echo json_encode($presents); ?>;

		var combo_presents_rows = "";
		for (var i = 0; i < jArray_presents.length; i++)
		{
			combo_presents_rows += "<option value='" + jArray_presents[i]["event_present_id"] + "'>" + jArray_presents[i]["event_present_name"] + "</option>";
		}

		$("#cmb_present").html(combo_presents_rows);

		$('#cmb_present').multiselect({
		    includeSelectAllOption: true
		});

		///////////////////////////////////////////////////////////// FILL presents (also included)
		

		///////////////////////////////////////////////////////////// FILL benefits
		var jArray_benefits =   <?php echo json_encode($benefits); ?>;

		var combo_benefits_rows = "";
		for (var i = 0; i < jArray_benefits.length; i++)
		{
			combo_benefits_rows += "<option value='" + jArray_benefits[i]["event_benefit_id"] + "'>" + jArray_benefits[i]["event_benefit_name"] + "</option>";
		}

		$("#cmb_benefits").html(combo_benefits_rows);
		
		$('#cmb_benefits').multiselect({
		    includeSelectAllOption: true
		});
		///////////////////////////////////////////////////////////// FILL benefits
		

		///////////////////////////////////////////////////////////// FILL req
		var jArray_reqs =   <?php echo json_encode($reqs); ?>;

		var combo_reqs_rows = "";
		for (var i = 0; i < jArray_reqs.length; i++)
		{
			combo_reqs_rows += "<option value='" + jArray_reqs[i]["event_requirement_id"] + "'>" + jArray_reqs[i]["event_requirement_name"] + "</option>";
		}

		$("#cmb_reqs").html(combo_reqs_rows);
		
		$('#cmb_reqs').multiselect({
		    includeSelectAllOption: true
		});
		///////////////////////////////////////////////////////////// FILL req
		

		///////////////////////////////////////////////////////////// FILL target_audiences
		var jArray_target_audiences =   <?php echo json_encode($target_audiences); ?>;
 
		var combo_target_audiences_rows = "";
		for (var i = 0; i < jArray_target_audiences.length; i++)
		{
			combo_target_audiences_rows += "<option value='" + jArray_target_audiences[i]["event_target_audience_id"] + "'>" + jArray_target_audiences[i]["event_target_audience_name"] + "</option>";
		}

		$("#cmb_tauds").html(combo_target_audiences_rows);
		
		$('#cmb_tauds').multiselect({
		    includeSelectAllOption: true
		});
		///////////////////////////////////////////////////////////// FILL target_audiences
		

		///////////////////////////////////////////////////////////// FILL sponsors
		var jArray_sponsors =   <?php echo json_encode($sponsors); ?>;
 
		var combo_sponsors_rows = "";
		for (var i = 0; i < jArray_sponsors.length; i++)
		{
			combo_sponsors_rows += "<option value='" + jArray_sponsors[i]["event_sponsor_id"] + "'>" + jArray_sponsors[i]["event_sponsor_name"] + "</option>";
		}

		$("#cmb_sponsors").html(combo_sponsors_rows);
		
		$('#cmb_sponsors').multiselect({
		    includeSelectAllOption: true
		});
		///////////////////////////////////////////////////////////// FILL sponsors
		
		///////////////////////////////////////////////////////////// FILL speakers
		var jArray_speakers =   <?php echo json_encode($speakers); ?>;
  
		var combo_speakers_rows = "";
		for (var i = 0; i < jArray_speakers.length; i++)
		{
			combo_speakers_rows += "<option value='" + jArray_speakers[i]["event_speaker_id"] + "'>" + jArray_speakers[i]["event_speaker_name"] + "</option>";
		}

		$("#cmb_speakers").html(combo_speakers_rows);
		
		$('#cmb_speakers').multiselect({
		    includeSelectAllOption: true
		});
		///////////////////////////////////////////////////////////// FILL speakers
		
		
		///////////////////////////////////////////////////////////// EDIT RECORD
		var jArray = <?php echo json_encode($row); ?>;

		if (jArray) {
			
			$('[name=eventsFORM_updateID]').val(jArray["event_id"]);
			$('[name=event_type_id]').val(jArray["event_type_id"]);
			
			var cmb_key_topic =  <?php echo json_encode($cmb_key_topic); ?>;
			$('#cmb_key_topic').multiselect('select', cmb_key_topic);

			var cmb_present =  <?php echo json_encode($cmb_present); ?>;
			$('#cmb_present').multiselect('select', cmb_present);

			var cmb_benefits =  <?php echo json_encode($cmb_benefits); ?>;
			$('#cmb_benefits').multiselect('select', cmb_benefits);

			var cmb_reqs =  <?php echo json_encode($cmb_reqs); ?>;
			$('#cmb_reqs').multiselect('select', cmb_reqs);

			var cmb_tauds =  <?php echo json_encode($cmb_tauds); ?>;
			$('#cmb_tauds').multiselect('select', cmb_tauds);

			var cmb_sponsors =  <?php echo json_encode($cmb_sponsors); ?>;
			$('#cmb_sponsors').multiselect('select', cmb_sponsors);

			var cmb_speakers =  <?php echo json_encode($cmb_speakers); ?>;
			$('#cmb_speakers').multiselect('select', cmb_speakers);
																		
		}
		///////////////////////////////////////////////////////////// EDIT RECORD
		
		//when form submitted (multi-selects belong there)
			$("#form_EVENTS").submit(function(e) {
			    e.preventDefault();
			 
			    ////////////////////////// validation
			    var form = $(this);
			    form.validate();
			 
			    if (!form.valid())
			        return;
			    ////////////////////////// validation
			 
			    var postData = $(this).serializeArray();
			    var formURL = $(this).attr("action");
			 	
				//if #multiple select# is exists merge to post!
				if($("#cmb_key_topic").length > 0) {
					postData.push({name: "cmb_key_topic", value : $("#cmb_key_topic").val()});
					postData.push({name: "cmb_present", value : $("#cmb_present").val()});
					postData.push({name: "cmb_benefits", value : $("#cmb_benefits").val()});
					postData.push({name: "cmb_reqs", value : $("#cmb_reqs").val()});
					postData.push({name: "cmb_tauds", value : $("#cmb_tauds").val()});
					postData.push({name: "cmb_sponsors", value : $("#cmb_sponsors").val()});
					postData.push({name: "cmb_speakers", value : $("#cmb_speakers").val()});
				}
				

			 	loading.appendTo($('#formEVENTS'));

			    $.ajax(
			    {
			        url : formURL,
			        type: "POST",
			        data : postData,
			        success:function(data, textStatus, jqXHR)
			        {
						loading.remove();

			            if (data=="00000")
						{	//refresh table @ main php
							$('#events_tbl').bootstrapTable('refresh');

						    //return to grid
							$("#events").show();
							$("#events_details").hide();
						}
			            else
			                alert("ERROR");
			        },
			        error: function(jqXHR, textStatus, errorThrown)
			        {
			        	loading.remove();
			            alert("ERROR - connection error");
			        }
			    });
			});
	}) /jQ ends
	
</script>

<body>
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Key Course Topics :</label>
								<select class="form-control" id="cmb_key_topic" multiple="multiple" name="cmb_key_topic[]"></select>
							</div>
						</div>
					</div>
					

					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Also Included :</label>
								<select class="form-control" id="cmb_present" multiple="multiple" name="cmb_present[]"></select>
							</div>
						</div>
					</div>
					
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Benefits :</label>
								<select class="form-control" id="cmb_benefits" multiple="multiple" name="cmb_benefits[]"></select>
							</div>
						</div>
					</div>
					
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Requirements :</label>
								<select class="form-control" id="cmb_reqs" multiple="multiple" name="cmb_reqs[]"></select>
							</div>
						</div>
					</div>
					
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Target Audiences :</label>
								<select class="form-control" id="cmb_tauds" multiple="multiple" name="cmb_tauds[]"></select>
							</div>
						</div>
					</div>
					
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Sponsors :</label>
								<select class="form-control" id="cmb_sponsors" multiple="multiple" name="cmb_sponsors[]"></select>
							</div>
						</div>
					</div>
					
					<div class="col-xs-6 col-md-4">
						<div class='form-group'>
							<div style="text-align: right;">
								<label> Speakers :</label>
								<select class="form-control" id="cmb_speakers" multiple="multiple" name="cmb_speakers[]"></select>
							</div>
						</div>
					</div>
				</div>
</body>



////////////////////////[save.php]
<?php
.
//insert/update the main record here
//when insert mark $trans_type=0
//when update mark $trans_type=1
.
.
	$res = $stmt->errorCode(); //get result
	 
	if ($res=="00000") //if success
	{
		if ($trans_type==0)
			$event_id =$db->lastInsertId();
		else
		{
			$event_id = $_POST['eventsFORM_updateID'];
	 
			//when update delete all to FK table!
			executeSQL($db, "delete from post_categories where post_id=?", array($post_id));
		}
        
	 
//////////////////////
//[event_key_topics]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_key_topic_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $key_topics = $_POST['cmb_key_topic'];

	    if (!empty($key_topics)) {
	 		
	 		$key_topics_arr = explode(',', $key_topics);

	        $sql = "INSERT INTO `event_key_topic_ties` (event_id, event_key_topic_id, event_key_topic_tie_order_id) VALUES (:event_id, :event_key_topic_id, :event_key_topic_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($key_topics_arr as $key_topics_id) {
 				
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_key_topic_id' , $key_topics_id);
					$stmt->bindValue(':event_key_topic_tie_order_id' , 0);
	 
	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    
//////////////////////
//[Also Included]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_present_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $presents = $_POST['cmb_present'];

	    if (!empty($presents)) {
	 		
	 		$presents_arr = explode(',', $presents);

	        $sql = "INSERT INTO `event_present_ties` (event_id, event_present_id, event_present_tie_order_id) VALUES (:event_id, :event_present_id, :event_present_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($presents_arr as $present_id) {
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_present_id' , $present_id);
					$stmt->bindValue(':event_present_tie_order_id' , 0);

	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    			
//////////////////////
//[Benefits]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_benefits_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $benefits = $_POST['cmb_benefits'];

	    if (!empty($benefits)) {
	 		
	 		$benefits_arr = explode(',', $benefits);

	        $sql = "INSERT INTO `event_benefits_ties` (event_id, event_benefit_id, event_benefit_tie_order_id) VALUES (:event_id, :event_benefit_id, :event_benefit_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($benefits_arr as $benefit_id) {
	            	
	            	$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_benefit_id' , $benefit_id);
					$stmt->bindValue(':event_benefit_tie_order_id' , 0);

	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    			
//////////////////////
//[Reqs]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_requirement_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $reqs = $_POST['cmb_reqs'];

	    if (!empty($reqs)) {
	 		
	 		$reqs_arr = explode(',', $reqs);

	        $sql = "INSERT INTO `event_requirement_ties` (event_id, event_requirement_id, event_requirement_tie_order_id) VALUES (:event_id, :event_requirement_id, :event_requirement_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($reqs_arr as $req_id) {
	            	
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_requirement_id' , $req_id);
					$stmt->bindValue(':event_requirement_tie_order_id' , 0);

	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    			
//////////////////////
//[Tauds]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_target_audience_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $tauds = $_POST['cmb_tauds'];

	    if (!empty($tauds)) {
	 		
	 		$tauds_arr = explode(',', $tauds);

	        $sql = "INSERT INTO `event_target_audience_ties` (event_id, event_target_audience_id, event_target_audience_tie_order_id) VALUES (:event_id, :event_target_audience_id, :event_target_audience_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($tauds_arr as $taud_id) {
	            	
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_target_audience_id' , $taud_id);
					$stmt->bindValue(':event_target_audience_tie_order_id' , 0);

	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    			
//////////////////////
//[Sponsors]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_sponsor_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $sponsors = $_POST['cmb_sponsors'];

	    if (!empty($sponsors)) {
	 		
	 		$sponsors_arr = explode(',', $sponsors);

	        $sql = "INSERT INTO `event_sponsor_ties` (event_id, event_sponsor_id, event_sponsor_tie_order_id) VALUES (:event_id, :event_sponsor_id, :event_sponsor_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($sponsors_arr as $sponsor_id) {
	            	
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_sponsor_id' , $sponsor_id);
					$stmt->bindValue(':event_sponsor_tie_order_id'  , 0);
					
	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	    			
//////////////////////
//[Speakers]
//////////////////////
        //when update delete all to FK table!
        executeSQL($db, "delete from event_speaker_ties where event_id=?", array($event_id));
	 
	    //get key_topics
	    $speakers = $_POST['cmb_speakers'];

	    if (!empty($speakers)) {
	 		
	 		$speakers_arr = explode(',', $speakers);

	        $sql = "INSERT INTO `event_speaker_ties` (event_id, event_speaker_id, event_speaker_tie_order_id) VALUES (:event_id, :event_speaker_id, :event_speaker_tie_order_id)";
	        if ($stmt = $db->prepare($sql)){
	 	
	            foreach ($speakers_arr as $speaker_id) {
	            	
					$stmt->bindValue(':event_id' , $event_id);
					$stmt->bindValue(':event_speaker_id' , $speaker_id);
					$stmt->bindValue(':event_speaker_tie_order_id' , 0);
					
	                $stmt->execute();    
	 
	                if($stmt->errorCode() != "00000"){
	                    echo $stmt->errorCode();
	                    exit;
	    			}        	    	    }	        }	    	  }
	}
	
	echo $res;