件名の通り、以下のようなエラーが出た
The page at 'URL' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'URL'. This request has been blocked; the content must be served over HTTPS.
原因はスラッシュ漏れ。FlaskもDjangoと同じ構造みたい。
How to Make an AJAX HTTPS GET Request Using jQuery - Stack Overflow
間違い
url : '/search'
正解
url : '/search/'
