Visualforce onclick doesn’t execute action or rerender

I’m having a problem. Up till’ now, I was using my own jQuery build to do this. Meanwhile, I was told to change it to jQuery validation plugin. It was working before but now I’ve been stuck in trying to make the action of the command execute and rerender (it doesn’t even rerender at the moment). The field validation work fine, just the submit is messing me all up. I’d appreciate any help or advice you could give.

delete confirmation message on anchor tag

As a new learner, i have some basic problems which i want to clear out.
1)i have shown student data, in tabular format.
2)in the last of below code i have provided two anchor tags.
3)among them first one redirects on update page whether the second one directly executes delete query on click without confirmation).
so what i want ,when i click on delete link, browser should ask me for confirmation,
if yes,
then delete and redirect to login page.
if no,
stay on same page

Parametrize on() function jquery

I have different user inputs. When one of them is changed I want to capture a change event only to its value.
I’m trying to customize the code of an existing product. My goal is to pop up an error div when user input is wrong but my current code adds the error div under all inputs.
This code works on all inputs but I want that it works only on input has title of label parent that contains ‘Valore’.

Else statement not readjusting height and width of img after If statement adjusts the img

When the user scrolls more than 50px down the viewport, my if statement adjusts a bunch of elements in the header. Once the user scrolls back to less than 50px, it readjusts back to normal with an else statement. Currently, everything functions fine besides my img height and width within the else statement. For some reason, the code doesn’t bounce back to 60px in height after shifting to 30px in the if/else statement. Please let me know what you think is wrong with the else statement. I assume is has something to do with catching images specifically.