Javascript - passing the entire query string from one php page to another

I have a php page which receives form input and displays it in a printable format. I have an email button which should take the already received POST data and pass it along to a 2nd php page which simply sends it in an email.

I have the two pages built and would like to simply pass the existing url query string to the second page but am stuck on the best way to do this via POST (don’t want to spawn another page in the browser).

So far, I have my query string packaged up via;

but have not been able to get various ajax and other examples like the following to work:

var SearchString =;alert(SearchString);
var url = "emailPrintable.php";"GET", url+"?"+SearchString, true);