Wouldn't it suffice to alter the
action of the sourrounding form?
Or check what the page normally does before sending the form. Some SharePoint pages declare a
WebForm_OnSubmit-function that will start the process of checking all required fields and return a boolean indicating if the validation was successful, or not.
if you, i.e. take a look at the advanced settings page of a list (
/_layouts/15/advsetng.aspx) the HTML looks like this:
<!-- many cool input elements... -->
here you can see first in the
var valid = WebForm_OnSubmit() you'll get the current validation-state of the page (and most probably trigger all the little red error-warnings in the page...).
What you can also see, is the
action=... of the form. This is the url the postback will go to, if the form is to be submitted. So if you have a page, whose save-button needs to send the data to a different location than the one intended by the page you should try to modfy the
action of the form instead of the save button.
Given the above example and using jQuery the modification is fairly simple: