getting the GUID of current form

java script:

function showvalue(message,value)
{
prompt(message,value);
}

Pls check the Spellings correctly

<JavaScriptFunction FunctionName="showvalue" Library="$webresource:new_forguid" >
                <StringParameter Value="form guid:"/>
                <CrmParameter Value="PrimaryItemIds"/>
              </JavaScriptFunction>

by using this will get the current opened form id.