Retrieve Metadata for specific entity

this example uset to get via Javascript information regarding specific entity.
var xml = "" +
"" +
"" +
GenerateAuthenticationHeader() +
" " +
" "
+
" " +
" 00000000-0000-0000-0000-000000000000" +
" EntityOnly" +
" account" +
" false" +
" " +
" " +
" " +
"" +
"";

var xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");

xmlHttpRequest.Open("POST", "/mscrmservices/2007/MetadataService.asmx",
false);
xmlHttpRequest.setRequestHeader("SOAPAction","http://schemas.microsoft.com/crm/2007/WebServices/Execute");
xmlHttpRequest.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
xmlHttpRequest.setRequestHeader("Content-Length", xml.length);
xmlHttpRequest.send(xml);

var resultXml = xmlHttpRequest.responseXML;
alert(resultXml.xml);

Enjoy,
Rami Heleg