https://www.pasadenachristian.org/pro/responsive/js/validation.js?v=1

1function set_checkbox_requirements() {
2	var answers_num = $('.required_answers',$(this).closest('fieldset')).val();
3	var checked_num = $(':checked',$(this).closest('fieldset')).length;
4	
5	if(typeof answers_num != "undefined") { //only check for required answers if required answers exist
6		if(checked_num >= answers_num) {
7			//$('span:first-child .form-checkbox',$(this).closest('fieldset')).get(0).setCustomValidity('');
8			//$('span:first-child .form-checkbox',$(this).closest('fieldset')).removeAttr('required');
9			//console.log($('.form-checkbox',$(this).closest('fieldset')));
10			var temp = $('.form-checkbox',$(this).closest('fieldset'));
11			$('input.form-checkbox',$(this).closest('fieldset')).each(function(){$(this).removeAttr('required');});
12			$('input.form-checkbox',$(this).closest('fieldset')).each(function(){$(this)[0].setCustomValidity('');});
13		} else {
14			if(typeof answers_num != "undefined" && answers_num > 0) {
15				optiontext = 'option';
16				if(answers_num > 1) optiontext = 'options';
17				//$(this).get(0).setCustomValidity('You must select at least ' + answers_num + ' ' + optiontext);
18				$('input.form-checkbox',$(this).closest('fieldset')).each(function(){
19					$(this)[0].setCustomValidity('You must select at least ' + answers_num + ' ' + optiontext);
20				});
21			}
22			//console.log($('.form-checkbox',$(this).closest('fieldset')));
23			var temp = $('.form-checkbox',$(this).closest('fieldset'));
24			$('input.form-checkbox',$(this).closest('fieldset')).each(function(){$(this).attr('required',true);});
25			
26		}
27	}
28}
29
30$(document).ready(function() {
31	$('.responsive-form').each(function() {
32		var myForm = $(this);
33		$('fieldset .form-checkbox',myForm).each(function() {
34			var answers_num = $('.required_answers',$(this).closest('fieldset')).val();
35			if(typeof answers_num != "undefined" && answers_num > 0) {
36				optiontext = 'option';
37				if(answers_num > 1) optiontext = 'options';
38				$(this)[0].setCustomValidity('You must select at least ' + answers_num + ' ' + optiontext);
39			} 
40		});
41	});
42	$('.responsive-form .form-checkbox').on('change', set_checkbox_requirements);
43	$('.responsive-form .form-checkbox').each(set_checkbox_requirements);
44});
45
46//returns true if the email is valid and false if it is not
47function validate_email(email) {
48	const mailExp = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;        
49	  return mailExp.test(email);
50}
51
52//returns an array containing any invalid emails from the list; array will be length zero if all are valid
53function validate_email_list(email_list) {
54	var invalid_emails = [];
55	
56	comma = email_list.indexOf(",");
57	semicolon = email_list.indexOf(";");
58
59	if (comma >= 0 && semicolon >= 0) {
60		//they used both commas and semicolons
61		var email_array = [];
62		var temp_array = email_list.split(",");
63		for (let i = 0; i < temp_array.length; i++) {
64			var cur_array = temp_array[i].split(';');
65			email_array.concat(cur_array);				
66		}					
67	} else if (comma >= 0) {
68		var email_array = email_list.split(",");
69	} else if (semicolon >= 0) {
70		var email_array = email_list.split(";");
71	} else {
72		//just a single entry
73		var email_array = [];
74		email_array.push(email_list);
75	}
76
77	for (let i = 0; i < email_array.length; i++) {
78		var cur_email = email_array[i].trim()
79		result = validate_email(cur_email);
80		if (!result) {
81			invalid_emails.push(cur_email);
82		}
83	}
84	return invalid_emails;
85}