title: How to get data from my Server to my JSP using javascript?
body: <p>I'm working on a map creation web app using javascript and JSP's. At some point I want my users to be able to save the map they've created to my db, but I have to check whether or not the name of the map already exists. 
  I need do so without leaving the page itself or I'll lose about the map stored in that JSP.</p>
  
  <p>So the question is: How can I get a response from my server without having to change page/url?</p>