hi all i have problem javacript on firefox i have page default.aspx is <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Untitled Page</title> <link href="../../../common/baseStyle.css" rel="stylesheet" type="text/css" /> <link href="../../../common/baseStyle.css" rel="stylesheet" type="text/css" /> <link href="../../../common/baseStyle.css" rel="stylesheet" type="text/css" /> <script language="javascript" type="text/javascript"> function postback() { var demo; var isIE=document.all?true:false; var isDOM=document.getElementById?true:false; if(isDOM){ parent.frames['ifmap'].document.form11.statusZoom.value = " gan lai gia tri"; parent.frames['ifmap'].demo(); //alert(demo); } else if(isIE) { parent.frames['ifmap'].document.form11.statusZoom.value = "demo ne"; parent.demo(); } } </script> </head> <body> <form name="form1" method="post" action="main.html" id="form1"> <input type="button" id="Button1" name="demoss" value="Refresh Map" onclick="postback()" /> <table align="center" id="Table1" border="0" bgcolor="#ffffff" cellspacing="0" cellpadding="0" width="780"> <tr> <td style="border: 1px solid" bordercolor="000"> <iframe height="460" width="600" id="ifmap" src="iframedemo.html" frameborder="0" scrolling="no"></iframe> </td> </tr> </table> </form> </body> </html> on the iframe "Map.aspx" contain html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>Moblie Station Demo</title> <script language="javascript" type="text/javascript"> function demo() { alert(document.forms['form11'].elements['statusZoom'].value); } </script> </head> <body style="BODY" > <form name="form11" method="post" action="demo1.aspx" id="form11"> <input type=button value="aaaaaa" onclick="demo()"/> <input type="hidden" id="statusZoom" value="demodemo"/> </form> </body> </html> when i assgin value to "statusZoom" by javacript on the page Default.aspx parent.ifmap.document.forms['f2'].elements['Param'].value = "demo"; Note :"f2" is name from on page Map.aspx. it run ok on IE but on Firefox it not run and have error arent.ifmap has no properties ??????? how could i assgin value on firefox.