How can I display the progress of an ASP. NET page that has been loaded for a long time in a client browser?

For ASP. NET pages that have been loaded for a long time, we can display a progress bar in the client browser to show that the page is being loaded. The specific implementation process is as follows:
Create a project named WebPortal. In the project type, select Visual C # Project or Visual Basic project;
Select an ASP. NET Web application from the template type;
Enter: http: // localhost/WebPortal;
Add a new project: a Web form named ShowProgress.
Add any other Web server controls on your Web form ShowProgress. aspx.
Right-click ShowProgress. aspx, click "View code", and enter:
Visual C #. NET code using System. Threading;
Visual Basic. NET code Imports System. Threading
In the Page_Load event, enter: Visual C #. NET code Response. Write ("");
Response. Write ("_");
Response. Write ("");
Response. Write ("mydiv. innerText = '';");
Response. Write (";");
Response. Write ("var dots = 0; var dotmax = 10; function ShowWait ()");
Response. Write ("{var output; output = 'loading page'; dots ++; if (dots> = dotmax) dots = 1 ;");
Response. Write ("for (var x = 0; x <dots; x ++) {output + = '·';} mydiv. innerText = output ;}");
Response. Write ("function StartShowWait () {mydiv. style. visibility = 'visible ';");
Response. Write ("window. setInterval ('ShowWait ()', 1000 );}");
Response. Write ("function HideWait () {mydiv. style. visibility = 'did ';");
Response. Write ("window. clearInterval ();}");
Response. Write ("StartShowWait ();");
Response. Flush ();
Thread. Sleep (10000 );
Visual Basic. NET code Response. Write ("")
Response. Write ("_")
Response. Write ("")
Response. Write ("mydiv. innerText = '';")
Response. Write (";")