XML ajax IE error

[fanikols]

I have XML code and I want to display some txt every 5 seconds on my home page,XML is connect through php code to mysqlphp server(DB) which the txt stored in.I ran the code in firefox,chrome is working fine, however when I ran it in IE(all versions) I got this error:SCRIPT5007: Unable to get property 'documentElement' of undefined or null reference displayxml.js, line 11 character 2what should I do to run my ajax xml code on IE browser?Thanks