Net-the focus cannot be moved because the control is currently invisible, disabled, or the type is not allowed.

Today, I am working on a project. There is a page that uses the Ajax modalpopupextender control. I put a few text boxes in it with verification, and set the setfocusonerror = "true" attribute of the verification control. A script error was reported during the test. "The focus cannot be shifted because the control is currently invisible, disabled, or the type is not allowed ". After several minutes of analysis, I came to the conclusion that apart from saving useful data, other operations such as focus () are not allowed. Setfocusonerror = "false" solved.