"Knock Knock - Doris" joke

Knock Knock
Who's there!
Doris!
Doris who?
Doris jammed again! Knock Knock
Who's there!
Doris!
Doris who?
Doris dropping off its hinges with all this knocking! Knock Knock
Who's there!
Doris!
Doris who?
Doris slammed on my finger. Ouch!