Explain about the pagemessage component in Apex?

The apex:pagemessage element generates and presents all error codes from all elements on the current website page, with SF styling applied. When the apex:pagemessage element is used in a Visualforce page, this element will have various properties that will be used.

Apex pagemessage Component Attributes :

Title The title of the Error will be displayed.
Summary The summary of the title Error Message is printed with this parameter.
Detail This will display the Error's detailed description.
Severity This parameter is an Error logotype. Error, Warning, Info, and Confirm are the several types of error severity.
Strength The intensity message logo is available in sizes ranging from 1 to 3.
Rendered This property determines whether or not the element should be enabled.
Escape A Boolean value indicates whether vulnerable HTML and XML elements should be encoded in the HTML produced by this module.
Show Detail It's a Boolean type that determines whether the particular location of the messages is displayed; by default, it's false.