How to use struts2 submit tag as button without submitting the form?
If you are using s:submit tag the rendered HTML output is either input or button tag but the type is submit except for the image type. You can use the code to execute javascript onclick event that doesn't submit the form.
<s:submit type="button" onclick="return false;"/>
Have you tried preventDefault()?
$("btnSave").click(function(e){ e.preventDefault(); //..rest of the code});