FileUpload Javascript Validation

Hi friends,

It's better to avoid validation through server side even we can do through client side.

this code is for fileupload validation . It wil accept only ".xls", ".xlsx", ".XLS",".XLSX" 

Fileuploader Id is FileUpload1 

Code

    <script type="text/javascript">        function CheckFileExtension() {             var ctrlUpload = document.getElementById('<%=FileUpload1.ClientID%>'); //Does the user browse or select a file or not.             if (ctrlUpload.value == '') {alert("Select a file first!");ctrlUpload.focus();return false;} //Extension List for validation. Add your required extension here with comma separator.             var extensionList = new Array(".xls", ".xlsx", ".XLS", ".XLSX"); //Get Selected file extension             var extension = ctrlUpload.value.slice(ctrlUpload.value.indexOf(".")).toLowerCase(); //Check file extension with your required extension list.             for (var i = 0; i < extensionList.length; i++) { if (extensionList[i] == extension) return true; } alert("You can only upload an Excel File Type i.e.\n" + extensionList.join(" or\n")); ctrlUpload.focus(); return false;         } </script>

now call the function CheckFileExtension() on button onclientclick event it solved 

have a nice day 'n happy coding :)