<! 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> No title page </title>
<Script type = "text/javascript" language = "javascript">
Function CheckFileType ()
{
Var objButton = document. getElementById ("Button1"); // upload button
Var objFileUpload = document. getElementById ('fileupload1'); // FileUpload
Var objMSG = document. getElementById ('msg '); // The DIV used to display the prompt information
Var FileName = new String (objFileUpload. value); // file name
Var extension = new String (FileName. substring (FileName. lastIndexOf (".") + 1, FileName. length); // File extension
If (extension = "jpg" | extension = "JPG") // you can add an extension.
{
ObjButton. disabled = false; // enable the upload button
ObjMSG. innerHTML = "";
}
Else
{
ObjButton. disabled = true; // disable the upload button
ObjMSG. innerHTML = "select the correct file ";
}
}
</Script>
</Head>
<Body>
<Form id = "form1" runat = "server">
<Div>
<Div id = "msg"> </div>
<Asp: Button ID = "Button1" runat = "server" Text = "Upload" Enabled = "False"/>
<Br/>
<Asp: FileUpload ID = "FileUpload1" runat = "server" onChange = "javascript: CheckFileType ();"/>
</Div>
</Form>
</Body>
</Html>
