Response.Write("<script>window.onload=function (){if(confirm(\"该文件已经存在，确定要替换吗吗?\")){document.getElementById(\"hidIsSave\").value = \"1\" }else {document.getElementById(\"hidIsSave\").value = \"0\"}}</script>");
???????????????if (hidIsSave.Value == "1")
???????????????{
???????????????????File.Delete(Server.MapPath(FileName));
???????????????????fuload.SaveAs(Server.MapPath(FileName));
???????????????}
???????????????else
???????????????{
???????????????}
.net 后台判断是否要替换
原文地址：https://www.cnblogs.com/balcon/p/10240832.html