reqId unique request identifier
Returns a single property named catalogRecord.exists . The property value is set to "1" if the specified catalog entry exists in the image or default catalog, otherwise it is set to "0". req=exists requests against the /is/content context will indicate the presence or absence of a specified record in the static content catalog.
Other commands in the request string are ignored. The HTTP response is cacheable with the TTL based on attribute::NonImgExpiration .
Requests that support JSONP response format lets you specify the name of the JS callback handler using the extended syntax of req= parameter:
req=...,json [&handler = reqHandler ]
<reqHandler> is the name of the JS handler that is present in the JSONP response. Only a-z, A-Z, and 0-9 characters are allowed. Optional. Default is s7jsonResponse .