Using web.javascript_eval_expr Statement
Example
web.javascript_eval_expr('window.showModelessDialog("help/SomeFile.html", "''", "dialogLeft:120px; dialogTop:260px; dialogWidth:800px; dialogHeight:455px; scroll-y:on; resizable:yes; status:no; help:no;");');
web.javascript_eval_expr('window.showModalDialog("help/SomeFile.html", "''", "dialogLeft:120px; dialogTop:260px; dialogWidth:800px; dialogHeight:455px; scroll-y:on; resizable:yes; status:no; help:no;");');
web.javascript_eval_expr('window.open("help/SomeFile.html", "WinHelp", "location=no,menubar=no,left=220,top=260,width=800,height=455,toolbar=no,resizable=yes,scrollbars=yes");');