Bool incomingExists(String key, DataSource ds)
Arguments
key: The key to checkds: The source for user-supplied data
Usage
Returns true if the key exists in the data source, and false otherwise.
// GET /example.cgi?a=1;b=3;b=5;z=;z;z
val = incomingExists("a",DataGet);
// val = true
val = incomingExists("b",DataGet);
// val = true
val = incomingExists("c",DataGet);
// val = false
val = incomingExists("z",DataGet);
// val = trueThis is useful for avoiding Exceptions when using incomingData or incomingValue, or for checking if a checkbox has been selected.
