Solution:
The answers online are all unreliable after I have verified. Everyone will know in the future. The method for Flexigrid to not display data in IE is: specify the way Ajax requests data as Get
In addition, flexigrid is not that it cannot use the "post" method to send data, but the "post" method must have data for post in IE. For example, you can use the post method when paging. If you have no data to send, you must use the "get" method. Other browsers may not have strict requirements on this, and IE requirements are strict: