jQuery(function($) {
  $(".stick2").sticky({ topSpacing: 50 }); // stop 50px from top
  $(".stick3").sticky({ topSpacing: 100 }); // stop 100px from top
});

<?xml version="1.0" encoding="UTF-8"?>
<form>
<fields name="params">
	<fieldset name="basic">
          <field type="radio" name="showbacktotop" class="btn-group btn-group-yesno" default="1" label="Show Top Button" />
	</fieldset>
</fields>
</form>

<?php defined('_JEXEC') or die;
$btt = ''; //define null value for the variable to avoid php errors
if( $this->params->get('showbacktotop') ) {
  $btt = '<a href="#top">Top</a>';
}

<?xml version="1.0" encoding="UTF-8"?>
<extension version="3.6" type="file" method="upgrade">
	<name>SunnyDay For Protostar</name>
	<author>MyDesign</author>
	<authorEmail>mail@mydesign.com</authorEmail>
	<authorUrl>www.mydesign.com</authorUrl>
	<copyright>(C) 2018 MyDesign.com. All rights reserved</copyright>
	<license>GNU General Public License version 2 or later; see LICENSE.txt</license>
	<version>1.0</version>
	<creationDate>August 2018</creationDate>
	<description>SunnyDay Theme to make the site nice</description>
	
	<updateservers>
		<server type="extension" priority="1" name="SunnyDay Theme For Protostar">http://www.url-to-updatexml.com/proto-options-sunnyday.xml</server>
	</updateservers>
	
	<languages folder="language">
		<language tag="en-GB">en-GB/en-GB.files_cmse_sunnyday.ini</language>
		<language tag="en-GB">en-GB/en-GB.files_cmse_sunnyday.sys.ini</language>
	</languages>

	<fileset>
		<files>
			<folder>cmse_sunnyday</folder>
			<folder>language</folder>
			<folder>params</folder>
			<file>cmse_sunnyday.php</file>
		</files>
	</fileset>
	
	<scriptfile>install.php</scriptfile>

</extension>

<?php defined( '_JEXEC' ) or die;
/**
* @package		cmse_proto_option theme
* @copyright	Copyright (C) CmsEnergizer.com All rights reserved.
* @license		GNU General Public License version 2 or later; see http://www.gnu.org/licenses/
**/

class SpecialInstallerScript 
{
	
	public function preflight($action) 
	{
		
		if( in_array($action, ['install','update'] ) ) {
			// check for installation of cmse_proto_options plugin. 
			// Scrap installation of this theme if the plugin is not installed
			if( !JFolder::exists(JPATH_ROOT.'/templates/protostar/custom') ) {
				JFactory::getApplication()->enqueueMessage(JText::_('This theme requires CMSE Proto Options plugin. It is free <a href="http://cmsenergizer.com/extension-directory/joomla-protostar-template-custom-styling-plugin" target="_blank">Get it now</a>'), 'warning');

				return false;
			}
		}
		
	}

    public function postflight() 
	{
		// name of parent folder
		$parentname = basename(dirname(__FILE__));
		$themename  = simplexml_load_file(JUri::root().'administrator/manifests/files/'.$parentname.'.xml');
		
		$themesrc    = __DIR__.'/'.$parentname;
		$templatesrc = __DIR__.'/'.$parentname.'.php';
		$paramsrc    = __DIR__.'/params/';

		$themedest	  = JPATH_ROOT.'/templates/protostar/custom/themes/'.$parentname;
		$templatedest = JPATH_ROOT.'/templates/protostar/custom/templates/'.$parentname.'.php';
		$paramdest    = JPATH_ROOT.'/templates/protostar/custom/params/';
		
		if( JFolder::exists($themesrc) )
			JFolder::move($themesrc, $themedest);
		
		if( JFile::exists($templatesrc) )
			JFile::move($templatesrc, $templatedest);
		
		if( JFile::exists($paramsrc.$parentname.'.xml')
			JFile::move($paramsrc.$parentname.'.xml', $paramdest.$parentname.'.xml');
		
		if( JFile::exists($paramsrc.$parentname.'.php')
			JFile::move($paramsrc.$parentname.'.php', $paramdest.$parentname.'.php');
		
		JFactory::getApplication()->enqueueMessage(
			JText::_('Successfully installed Protostar custom theme named - <strong>'.ucfirst($themename->name).'</strong>')
			);
    }
	
	public function uninstall() 
	{
		$parentname = basename(dirname(__FILE__));
		$themename  = simplexml_load_file(JUri::root().'administrator/manifests/files/'.$parentname.'.xml');
		
		$themesrc    = JPATH_ROOT.'/templates/protostar/custom/themes/'.$parentname;
		$templatesrc = JPATH_ROOT.'/templates/protostar/custom/templates/'.$parentname.'.php';
		$paramsrc    = JPATH_ROOT.'/templates/protostar/custom/params/';
		
		if( JFolder::exists($themesrc) )
			JFolder::delete($themesrc, true);
		
		if( JFile::exists($templatesrc) )
			JFile::delete($templatesrc, true);
		
		if( JFile::exists($paramsrc.$parentname.'.xml') )
			JFile::delete($paramsrc.$parentname.'.xml', true);
		
		if( JFile::exists($paramsrc.$parentname.'.php') )
			JFile::delete($paramsrc.$parentname.'.php', true);
		
		JFactory::getApplication()->enqueueMessage(
			JText::_('Successfully uninstalled Protostar custom theme named - <strong>'.ucfirst($themename->name).'</strong>')
			);
	}
}

<?php defined('_JEXEC') or die;

/**
* @package		plg_system_cmse_proto_options
* @copyright	Copyright (C) CmsEnergizer.com All rights reserved.
* @license		GNU General Public License version 2 or later; see http://www.gnu.org/licenses/
**/

?>
<!DOCTYPE html>
<html lang="<?php echo $this->language; ?>" dir="<?php echo $this->direction; ?>">
<head>
	<jdoc:include type="head" />
</head>
<body class="site <?php echo $bodyclass; ?>">
	<!-- Body -->
	<div class="body" id="top">
		<div class="container">
			<!-- Header -->
			<header class="header" role="banner">
				<div class="header-inner clearfix">
					<?php echo $showlogo; ?>
					<jdoc:include type="modules" name="position-0" style="raw" />
				</div>
			</header>
			
			<?php echo $widetitle; ?>
			
			<?php if( $this->countModules('position-1') ) { ?>
				<jdoc:include type="modules" name="position-1" style="raw" />
			<?php } ?>
			
			<jdoc:include type="modules" name="banner" style="cmsexhtml" />
			
			<div class="content-body row-fluid">
				<?php if ($pos8) : ?>
					<!-- Begin Sidebar -->
					<div id="sidebar" class="span<?php echo $lcol; ?>">
						<div class="sidebar-nav">
							<jdoc:include type="modules" name="position-8" style="cmsexhtml" />
						</div>
					</div>
					<!-- End Sidebar -->
				<?php endif; ?>
				<main id="content" role="main" class="span<?php echo $span; ?>">
					<!-- Begin Content -->
					<jdoc:include type="modules" name="position-3" style="cmsexhtml" />
					<jdoc:include type="message" />
					<jdoc:include type="component" />
					<div class="clearfix"></div>
					<jdoc:include type="modules" name="position-2" style="cmsexhtml" />
					<!-- End Content -->
				</main>
				<?php if ($pos7) : ?>
					<div id="aside" class="span<?php echo $rcol; ?>">
						<!-- Begin Right Sidebar -->
						<jdoc:include type="modules" name="position-7" style="cmsexhtml" />
						<!-- End Right Sidebar -->
					</div>
				<?php endif; ?>
			</div>
		</div>
	</div>
	<!-- Footer -->
	<footer class="footer" role="contentinfo">
		<div class="foot-inner container">
			<jdoc:include type="modules" name="footer" style="cmsexhtml" />
		</div>
	</footer>
	<jdoc:include type="modules" name="debug" style="none" />
</body>
</html>