Include the following script…
If you do not know how to do it the “right” way, you can go to Admin->Appearance->Editor->header.php
Copy & paste the below so that it is contained within the <head> tag. Be sure you do not include it within any <?php ?> tags. Any upgrades to the theme will potentially delete the code.
You can change 500 to whatever number of characters you want to check for. Be sure to change the substring values too.
<script src="https://code.jquery.com/jquery-1.10.2.min.js"></script>
<script>
$(document).ready(function () {
if ($("#featured_pet p").text().length > 500) {
var more = $("#featured_pet p").text().substring(100);
$("#featured_pet p").text($("#featured_pet p").text().substring(0, 100));
$("#featured_pet p").append("<div id=\"moreinfo\" style=\"display:none\">" + more + "</div>");
$("#featured_pet p").append("<a href=\"\" id=\"more\">more...</a>");
}
$("#more").click(function (event) {
event.preventDefault();
$("#moreinfo").slideToggle();
$("#more").hide();
});
});
</script>
