Take other pages attributes

Take other pages attributes

Hi good afternoon everyone!
I was wondering if it's possible to do this:
Bring some Value from other page
 
For example:
$(document).ready(function(){
 
var VALUE = $( www.jquery.com).("#p20").val();
 
 
});
 
Like that .. i dont know if it's possible to open a page and take the element of the page that has id="p20"
 
Thanks a lot!!