2Chainz

form.html

<form class="needs-validation">
                        <div class="form-group">
                            <input type="email" placeholder="Email address" class="form-control email-address-form my-3" autofocus required>
                        </div>
                        <div class="custom-control custom-checkbox">
                            <input type="checkbox" class="custom-control-input" id="__adult" checked>
                            <label for="__adult" class="custom-control-label">Yes, I am over 21 years old</label>
                        </div>
                        <div class="custom-control custom-checkbox">
                            <input type="checkbox" class="custom-control-input" id="__receiveNewsletter" checked>
                            <label for="__receiveNewsletter" class="custom-control-label">I would like to receive emails from Gas Cannabis on offers, events and promotions.</label>
                        </div>
                        <button class="btn btn-gold btn-block mt-4 w-100 mx-0" type="submit"> Go to website </button>
                    </form>

shopify.js

	<script type="text/javascript">
		// Checkbox validation on landing page
		var submit = document.getElementById('__validateVisitor'),
		    checkbox = document.getElementById('__adult'),
		    enableSubmit = function(e) {
		        submit.disabled = !this.checked
		    };

		checkbox.addEventListener('change', enableSubmit);
	</script>