javascript - jQuery UI sortable: determining in what order the items are

Question

Here is an interesting use of JavaScript: reordering items with drag and drop. The implementation itself in my page works fine, but is there a way to determine in which order the user put the items?

I'm asking because I want to load and save the item order in a cookie.

Answer 1

UPDATED 2012

FULL WORKING DEMO & SOURCE

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get the index position of the elements try to read this:

• Getting the position of the element in a list when it's drag/dropped (ui.sortable)

COOKIE plugin for jquery:

• http://plugins.jquery.com/project/cookie

JQUERY:

 $(function() {
    //coockie name
     var LI_POSITION = 'li_position';
       $('ul#sortable').sortable({
         //observe the update event...
            update: function(event, ui) {
              //create the array that hold the positions...
              var order = []; 
                //loop trought each li...
               $('#sortable li').each( function(e) {

               //add each li position to the array...     
               // the +1 is for make it start from 1 instead of 0
              order.push( $(this).attr('id')  + '=' + ( $(this).index() + 1 ) );
              });
              // join the array as single variable...
              var positions = order.join(';')
               //use the variable as you need!
              alert( positions );
             // $.cookie( LI_POSITION , positions , { expires: 10 });
            }
        });
     });?

HTML:

<ul id="sortable"> 
  <li id="id_1"> Item 1 </li> 
  <li id="id_2"> Item 2 </li> 
  <li id="id_3"> Item 3 </li> 
  <li id="id_4"> Item 4 </li> 
  <li id="id_5"> Item 5 </li> 
</ul>

PHP:

this is just an example but you got the idea: you may want use a database instead and use AJAX for get back the lis:

<?php  
//check if cookie is set..
if ( isset( $_COOKIE['li_position'] ) ) {
//explode the cockie by ";"...
$lis = explode( ';' , $_COOKIE['li_position'] );
// loop for each "id_#=#" ...
foreach ( $lis as $key => $val ) {
//explode each value found by "="...
$pos = explode( '=' , $val );
//format the result into li...
$li .= '<li id="'.$pos[0].'" >'.$pos[1].'</li>';
}
//display it
echo $li;
// use this for delete the cookie!
// setcookie( 'li_position' , null );
} else {
// no cookie available display default set of lis
 echo '
  <li id="id_1"> Fuji </li> 
  <li id="id_2"> Golden </li> 
  <li id="id_3"> Gala </li> 
  <li id="id_4"> William </li> 
  <li id="id_5"> Jordan </li> 
';
}
?>