<div id="testicontent" class="testi-content">
    <span class="short-text">Serious suction great results This is by far a Brilliant hoover! The suction is amazing I have a very hairy dog and my Son's husky stays most weekends. It picks up all the hair easily. I have had many branded hoovers, and this one is the most powerful I have used...</span>
    <span class="full-text" style="display: none;">I have had many branded hoovers and this one is the most powerful I have used it's been great with my cats' long white fur. No more rubbing carpet edges with a damp cloth! Plus, great if you suffer from Asthma or dust allergies; no more sneezing when using it as no dust escapes from it. The carpet cleaning is great for intensive cleaning and removes stains effortlessly. All cleaner accessories fit neatly into the water tank. It really has been a pleasure cleaning my floors and upholstery with The Aqua +. Thank you for choosing me to test out the Thomas Pet & Family cleaner and for making my hoovering a pleasant and satisfactory experience.</span>
</div>
<a href="javascript:void(0);" id="toggleBtn" class="toggle-btn">See More</a>
Step 2: jQuery Code

jQuery(document).ready(function($) {
    $('#toggleBtn').on('click', function() {
        var fullText = $('#testicontent .full-text');
        var shortText = $('#testicontent .short-text');

        if (fullText.is(':hidden')) {
            fullText.show();
            shortText.hide();
            $(this).text('See Less');
        } else {
            fullText.hide();
            shortText.show();
            $(this).text('See More');
        }
    });
});