Encryption

Hi,
May I know how to encrypt in .aspx file of Visual Studio 2003? I am able to encrypt in ASP & code behind page. But how about .aspx?
popUp = window.open('Calendar.aspx?formname=' + document.forms[0].name + '&id=' + idname + '&selected=' + document.forms[0].elements[idname].value + '&postBack=' + postBack, 'popupcal', 'width=205,height=248,left=200,top=250');
 
Thanks.
 
Regards,
Ling 
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