@Whittfield I appreciate the efforts you’ve made to help. Thank you. However, I have to report that nothing I’ve tried based on your suggestions has helped. I thought for the sake of others I’d complete this thread with my results.
First, I decided to download the latest beta (build 5) and enter the code you provided using Window–>Code Editor:
Second, I tested and found that it did not work; judging by my observation (in different browsers) that all audio players were still pre-loading (except the ones I manually changed attributes for).
Third, I checked to see if your approach makes changes to my Blocs project. It doesn’t (just as you said), confirming my notion that your approach is a “programming trick” which (while perhaps very cool) does not address my simpler question “how can I make this mass change in my Blocs project”
Therefore, I conclude that there is no way to change the attributes of multiple blocs (e.g., audio players) in a Blocs Project.
I’m not sure how posts get marked “SOLVED” but someone marked this that way despite my clear statement otherwise. Although I appreciate Whittfield’s help very much and have learned from him, his posts do not address whether one can make mass changes in a bloc project. The blocs project is unchanged by his approach, as clever as it may be.