[Answer]-Why is this variable not being passed in the POST request?

Your code looks like it’s looking for the id of the element with class delete_button. Does your template contain an element with that class? If so, what is its id? That is the value that should be passed as entryname, but if there’s no such element in your template then it would make sense that a value of None is being passed (as you mentioned in your comments). Try adding the delete_button class to your link tag.