Init, load, and prerender event execution sequence:

Init, load, and prerender event execution sequence: Init, load, and prerender event execution sequence:
1) Init event of the control
2) Init event on the page where the control is located
3) Load events on the page where the control is located
4) Load events of controls
5) prerender event on the page where the control is located
6) control prerender event

Rule:
1) The init event is triggered from the innermost control (including the user control and common control) to the outermost control (page, load, prerender, and other events are triggered from the outermost control to the innermost control;
2) The execution sequence of the same events between controls depends on the control's position on the page from left to right, from top to bottom.

Note:
1) Remember that the user control is also regarded as a control in the page;
2) using a user control as a special page, the user control itself and its contained controls follow the same rules;
3) Sometimes the onload event of the client body object is used in the client program (such as JavaScript). Note that this client event is the final execution, that is, all events on the server are executed only after they are executed.