var propup = function(o) {
    o.url = (typeof o.url == 'undefined') ? 'http://www.emanueleferonato.com/2007/09/21/complete-javascript-popup-opener/' : o.url;
    o.width = (typeof o.width == 'undefined') ? screen.width/2 : o.width;
    o.height = (typeof o.height == 'undefined') ? screen.height/2 : o.height;
    if((o.width<=1)&&(o.width>0)){o.width*=screen.width}
    if((o.height<=1)&&(o.height>0)){o.height*=screen.height}
    o.xpos = (typeof o.xpos == 'undefined') ? (screen.width/2)-(o.width/2) : o.xpos;
    o.ypos = (typeof o.ypos == 'undefined') ? (screen.height/2)-(o.height/2) : o.ypos;
    o.xoffset = (typeof o.xoffset == 'undefined') ? 0 : o.xoffset;
    o.yoffset = (typeof o.yoffset == 'undefined') ? 0 : o.yoffset;
    o.name = (typeof o.name == 'undefined') ? 'propup' : o.name;
    o.scrollbars = (typeof o.scrollbars == 'undefined') ? 'no' : o.scrollbars;
    o.resizable = (typeof o.resizable == 'undefined') ? 'no' : o.resizable;
    o.status = (typeof o.status == 'undefined') ? 'no' : o.status;
    o.locat = (typeof o.locat == 'undefined') ? 'no' : o.locat;
    o.toolbar = (typeof o.toolbar == 'undefined') ? 'no' : o.toolbar;
 
    if(o.xpos == "left"){o.xpos=0;}
    if(o.xpos == "right"){o.xpos = screen.width-o.width;}
   
    if(o.ypos == "top"){o.ypos=0;}
    if(o.ypos == "bottom"){o.ypos = screen.height-o.height;}
   
    o.xpos += o.xoffset
    o.ypos += o.yoffset
 
    var scrollbarstext = 'scrollbars = '+o.scrollbars+",";
    var resizabletext = 'resizable = '+o.resizable+",";
    var statustext = 'status = '+o.status+",";
    var locationtext = 'location = '+o.locat+",";
    var toolbartext = 'toolbar = '+o.toolbar+",";
 
    features = scrollbarstext+resizabletext+statustext;
    features = features + locationtext+toolbartext;
    features = features + 'width = '+o.width+',height = '+o.height;
    features = features + ',top = ' + o.ypos;
    features = features + ',left = ' + o.xpos;
       
    var win = null;
    win = window.open(o.url, o.name, features);
}