按钮没有触发第一次单击事件导致IE中的FileUpload控件导致奇怪的结果（ASP.NET）

I came across a strange situation with a button and the fileupload control in IE only. I did find a temporary way around this issue, however i would like to find out what called be the actual cause of the issue and if there is a better way around it then what i have done.I came across a strange situation with a button