var _popupid;
function closeMyPopup() {
    document.getElementById(_popupid).style.display = "none";
    document.getElementById("fixscr").style.display = "none";
 
}

function myPopupRelocate() {
    var scrolledX, scrolledY;
    if( self.pageYOffset ) {
        scrolledX = self.pageXOffset;
        scrolledY = self.pageYOffset;
    } else if( document.documentElement && document.documentElement.scrollTop ) {
        scrolledX = document.documentElement.scrollLeft;
        scrolledY = document.documentElement.scrollTop;
    } else if( document.body ) {
        scrolledX = document.body.scrollLeft;
        scrolledY = document.body.scrollTop;
    }

    var centerX, centerY;
    if( self.innerHeight ) {
        centerX = self.innerWidth;
        centerY = self.innerHeight;
    } else if( document.documentElement && document.documentElement.clientHeight ) {
        centerX = document.documentElement.clientWidth;
        centerY = document.documentElement.clientHeight;
    } else if( document.body ) {
        centerX = document.body.clientWidth;
        centerY = document.body.clientHeight;
    }
    
    var leftOffset = scrolledX + (centerX - 600) / 2;
    var topOffset = scrolledY + 100;

    document.getElementById("fixscr").style.top = scrolledY+ "px";
    document.getElementById("fixscr").style.left = scrolledX + "px";

    document.getElementById(_popupid).style.top = topOffset + "px";
    document.getElementById(_popupid).style.left = leftOffset + "px"; 
}

function ShowPopup(popupid) {
    _popupid=popupid;
    myPopupRelocate();
    document.getElementById(_popupid).style.display = "block";
    document.getElementById("fixscr").style.display = "";

    document.body.onscroll = myPopupRelocate;
    window.onscroll = myPopupRelocate;
    window.onresize =myPopupRelocate;
}