Javascript | clear input file value = file url

Included javascript function for clearing INPUT FILE contents!
I did it for disable uploading NON excel file (.xls).
(a message should be include...)

The CODE for ASP.NET:

<asp:FileUpload ID="txtFile" runat="server"
Enabled="true"
onchange="if (this.value.endsWith('.xls') == false) { this.parentNode.innerHTML = this.parentNode.innerHTML; }" />

The CODE HTML:

<input type="file" onchange="if (this.value.endsWith('.xls') == false) { this.parentNode.innerHTML = this.parentNode.innerHTML; }" style="width:216px;" />

Enjoy...
:)