make call to action sticky

call-to-action.js

jQuery(function($) {
    var $window = $(window),
        ctaPosition = parseInt($('#call-to-action').offset().top) - parseInt($('#call-to-action').height()) -  window.innerHeight,
        cta = $('#call-to-action');

    // Run this on scroll events.
    $window.scroll(function() {
	    console.log( $window.scrollTop() + ' - ' + ctaPosition );
        if ( $window.scrollTop() < ctaPosition ) {
            // Make the div sticky.
            cta.css({'position':'fixed','bottom':'0', 'width': '100%', 'z-index': '9999'});
        }
        else {
            // Unstick the div.
            cta.css({'position':'relative'});
        }
    });
    $window.scroll();
});