determine whether a value has been changed with multi select transfer

[johnmerlino]

Hey all,

 

I would like to know the best way to determine whether a value has been changed in a multi select transfer. For example, I have two select fields. User clicks on button to add an item to the right select element with id of select2 from the left select element with an id of select1. When they click update, it posts to a php method. This is where I am uncertain what to do. How can I check that they indeed added or removed items from the right select element and if they did, determine which ones were removed or added to make the reflected changes in the database?

 

This is what I have, but it's bad solution because it deletes all related records before it adds the ones it finds to the right select element:

 

	public function update(){

		$subcategory = new Category();
		$subcategory->where('id',$this->uri->segment(4))->get();

		$subcategory->delete($subcategory->related_category->get()->all);

		$new_parents = $this->input->post('catupload');
		$parent_category = new Category();
		$parent_category->where_in('controller',$new_parents)->get();

		$subcategory->save($parent_category->all);
	}

 

 

This is what the form elements look like:

 

		echo "You can add or remove one or many parents associated with this category:";
	echo "<div class='multiselect-transfer'>";
	echo form_multiselect('catadd[]',$other_cats,'','id="select1"');
	echo anchor('#','add >>','id="add"'); 
	echo "</div>";
	echo "<div class='multiselect-transfer'>";
	echo form_multiselect('catupload[]',$default_cats,'','id="select2"');
	echo anchor('#','<< remove','id="remove"');
	echo "</div>";		
	echo form_submit('submit','Update');
	echo form_close();

$other_cats variable holds array of categories that have not been asssociated with the current category being updated when this category was first created. The $default_cats variable holds an array of categories that have been associated with the current category being updated when this category was first created.

 

And the javascript:

 

	 
$().ready(function() {  
   $('#add').click(function() {  
    return !$('#select1 option:selected').remove().appendTo('#select2');  
   });  
   $('#remove').click(function() {  
    return !$('#select2 option:selected').remove().appendTo('#select1');  
   });  
  }); 

 

Thanks for response.