Drupal 8.x

Would like to use a Webform based on the “Registration” template to create a “member” that can become a user. Created a second form to approve and assign membership level (not sure how to add the block of this form to the submission page).

Two levels of “membership” (NO e-commerce required).

I'm trying to figure out how to leave an autocomplete field empty if there is no value. NULL didn't work - which I think is normal. But using ' ' didn't work either. How do I write my else statement below for when a field is empty?

A peek in the logs shows this error: Error: Call to a member function get() on null in ...

So I created a new theme and wrote my very simple .library.yml & .info.yml files.
All good and I 'installed' it.

To learn how to use JavaScript with Drupal, I wrote a simple alert ("Hello World"); javascript file.

All good, it appears on my Drupal page when I 'view source' so I know my yml files were written correctly.  When I click on the javascript file, it links fine & I see my code (see below)

I wrote a simple HTML form & added to a drupal block (i.e. add in FULL HTML) and onclick event button I call helloWorld().

I am running Drupal 8.5.3 and php 7.1. After my latest module update, update.php dies at https://mysite/update.php/selection

with the uninformative message: The website encountered an unexpected error. Please try again later. 

The log shows

Hi to all,

What I need to do seems very simple but I cannot find the answer. Here's my problem:

After exposing a date filter to visitor, (in Views), when I click on a specific date (on the mini-calendar offered by the "Better exposed Filters" module)  I need the articles published one day PRIOR to that date + the articles published on that date to show.

Seems simple? I cannot find the solution to this. I'm on this problem for more than 2 days now.

Can someone please help?

regards, 

How can I remove/replace special characters to the uploaded file name. Because the submitted email to the recipient with the link to the uploaded file, does not work if the is a special chars (#) in the file name. e.g. sample#.pdf