Write a normal JSF forward method to transfer data to the page bean of the pop-up page and return the mapping forward to the pop-up page (Till this point the code should be a complete one to open the page in the same window)
to open the popup use javascript function given below. Call the function in the onmousedown method of the link, popUpScreen('viewbase',this).
The first parameter is just a unique string.
function popUpScreen(targetScreenName,hyperlinkObject) {
newwindow = window.open('',targetScreenName, "height=450,width=650");
if (window.focus) {newwindow.focus()}
document.forms[0].target = targetScreenName;
hyperlinkObject.onclick();
document.forms[0].target = "";
}