Differences between RegisterStartupScript and RegisterClientScriptBlock?

RegisterStartupScript Places the script at the bottom of the asp.net page instead of at the top.
It registers the startup script with the Page object using a type, a key, a script literal, and a Boolean value indicating whether to add script tags.

RegisterClientScriptBlock inserts script immediately below the opening tag of the Page . means after <form> tag.
It registers the client script with the Page object using a type, key, script literal, and Boolean value indicating whether to add script tags.

Similarities:
Both RegisterStartupScript and RegisterClientScriptBlock is uniquely identified by its key and its type.
Scripts with the same key and type are considered duplicates. Only one script with a given type and key pair can be registered with the page. Attempting to register a script that is already registered does not create a duplicate of the script.