JavaScript - Popup windows

function Popup( url, height, width )
{
    var windowProperties = "toolbar = 0, scrollbars = 1, location = 0, statusbar = 0, menubar = 0, resizable = 1, width = " + width + ", height = " + height + ", left = 50, top = 50";
 
    return window.open( url, "", windowProperties );
}
 
function PopupScale( url, scale )
{
    // Default sizes.
    var height = 800;
    var width = 800;
    
    if ( window.screen ) 
    {
        height = window.screen.availHeight * scale / 100;
        width = window.screen.availWidth * scale / 100;
    }
 
    Popup( url, height, width );
}

Example: