Hi there. Few years back this question was solved, but in my case it doesn’t work. so after I submit form it’s disappearing. I have found the same topic and used answers from there. but it still doesn’t work.
Keep in mind that JS and CSS are very dependent on the actual structure of your html, so if you change something in the form, you will face the risk of breaking the JS or CSS code. Most of what I sent above will only break if you change the form field name/id or the class/id of the form.