Resolves the problem that the CalendarExtender control is obscured and adds a white background to avoid multi-layer effects. First put the control directly into the DIV and add z-index, but not valid. Find this article to solve the problem: http://blog.csdn.net/atian15/archive/2009/06/01/4231090.aspx asp.net Ajax CalendarExtender control is obscured by other div problem 1, problem description: When using asp.net ajax calendar controls, the control may appear partially obscured by other div containers, theoretically setting the div's Z-index attribute. But the key is how to set the Calendar control's z-index to the top level. 2, Solution: By looking up the source code of the Calendar control, you can find the style sheet named Calendar.css, the first line of the style sheet represents the style of the container for the entire calendar control, the code is as follows:. ajax__calendar_container {padding:4px; Position:absolute; Cursor:default; width:170px; font-size:11px; Text-align:center; Font-family:tahoma,verdana,helvetica; We simply rewrite the line style rule on the page to achieve the effect ... MyCalendar. Ajax__calendar_container {z-index:1000} and then set cssclass= "MyCalendar" in the control so that you can ... = = = Next, will. MyCalendar. Ajax__calendar_container {z-index:1000;} to read:. MyCalendar. ajax__calendar_container {z-index:3000; Background-color:white; Resolves multiple layers of visual impact. Http://four-corner.appspot.com