jQuery - *variable* is not defined
$('.share_button').live('click', function(e){
    $('#player').fadeOut('slow');
    var share_id = $(this).attr('id');

    $.ajax({
        type: 'GET',
        url: '/youtube.php',
        data: 'share='+ share_id,
        success: function(data) {
            //$('#params').html(data);
            //params = $('#params').html();
            param = data.split('--');
            share_title = param[0];
            share_description = param[1];
            share_picture = param[2];
            share_views = param[3];
        }
    });
    e.preventDefault();
    FB.ui(
    {
        method: 'feed',
        name: share_title,
        link: 'http://www.facebook.com',
        picture: share_picture,
        caption: share_views,
        description: share_description
    },
    function(response) {
        $('#player').show('slow');
    });
});

$('.share_button').live('click', function(e) {
    $('#player').fadeOut('slow');
    var share_id = $(this).attr('id');

    $.ajax({
        type: 'GET',
        url: '/youtube.php',
        data: 'share=' + share_id,
        success: function(data) {
            //$('#params').html(data);
            //params = $('#params').html();
            param = data.split('--');
            share_title = param[0];
            share_description = param[1];
            share_picture = param[2];
            share_views = param[3];

            FB.ui({
                method: 'feed',
                name: share_title,
                link: 'http://www.facebook.com',
                picture: share_picture,
                caption: share_views,
                description: share_description
            }, function(response) {
                $('#player').show('slow');
            });
        }
    });
    e.preventDefault();
});

$('.share_button').live('click', function(e) {
    $('#player').fadeOut('slow');
    var share_id = $(this).attr('id');
    var share_title;
    var share_... // do all your other share_*'s here as well.

    $.ajax({
        type: 'GET',
        url: '/youtube.php',
        data: 'share=' + share_id,
        success: function(data) {
            //$('#params').html(data);
            //params = $('#params').html();
            param = data.split('--');
            share_title = param[0];
            share_description = param[1];
            share_picture = param[2];
            share_views = param[3];

            FB.ui({
                method: 'feed',
                name: share_title,
                link: 'http://www.facebook.com',
                picture: share_picture,
                caption: share_views,
                description: share_description
            }, function(response) {
                $('#player').show('slow');
            });
        }
    });
    e.preventDefault();
});

$.ajax({
    type: 'GET',
    url: '/youtube.php',
    data: 'share='+ share_id,
    success: function(data) {
        param = data.split('--');
        share_title = param[0];
        share_description = param[1];
        share_picture = param[2];
        share_views = param[3];

        FB.ui({
            method: 'feed',
            name: share_title,
            link: 'http://www.facebook.com',
            picture: share_picture,
            caption: share_views,
            description: share_description
        },
        function(response) {
            $('#player').show('slow');
        });
    }
});