<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> < html xmlns = "http://www.w3.org/1999/xhtml" > < head runat = "server" > < title >无标题页</ title > </ head > < body > < form id = "form1" runat = "server" > < div > < asp:FileUpload ID = "FileUpload1" runat = "server" /> < asp:Button ID = "Button1" runat = "server" OnClick = "Button1_Click" Text = "Button" /> < input type = "file" lang = "de" /> < asp:CustomValidator ID = "CustomValidator1" runat = "server" ControlToValidate = "FileUpload1" ErrorMessage = "CustomValidator" ClientValidationFunction = "clientValidate" ></ asp:CustomValidator ></ div > </ form > < script type = "text/javascript" > function clientValidate(source,arguments){ var rgx=/(jpg|gif|bmp)/i; var sFilePath=document.getElementById("<%=FileUpload1.ClientID %>").value; var ext=sFilePath.substring(sFilePath.lastIndexOf(".")+1); arguments.IsValid=rgx.test(ext); } </ script > </ body > </ html >