jquery slider won't start

Hi all,
I’m trying to implement a jquery-slider in my frontpages header (https://bergdreh.de), I’ve got from a Tutorial. I don’t get any errors but it doesn’t show any effect either.
‘ve been searching my mistake for hours now and would be very thankful for hints and help.

I registered the script in functions.php:

function init_js() {
	if ( !is_admin()) {
		wp_deregister_script('jquery');
		wp_register_script('jquery','https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js',false,'1.4.2',true);
		wp_register_script('teaserchange',get_template_directory_uri().'/js/teaserchange.js','jquery','1',true);
		wp_enqueue_script('jquery');
		wp_enqueue_script('teaserchange');
	}
}

In loop-slider.php I wrote the sliders code:

[Code moderated as per the Forum Rules. Please use the pastebin]

And it’s powered by a teaserchange.js:

[Code moderated.]

style.css:

[CSS moderated as per the Forum Rules. Please just post a link to your site.]