<html xmlns="http://www.w3.org/1999/xhtml"> 	<head id="Head1" runat="server"> 	   <style type="text/css"> 	       html, body 	       { 	           font-family: Verdana; 	           font-weight: 10px; 	       } 	       .alert 	       { 	           color: Red; 	       } 	   </style>    <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.4.min.js" type="text/javascript"></script> 	   <script language="javascript" type="text/javascript">	  	   $(document).ready(function () { 	           var AllowedExtension = ['jpeg', 'jpg', 'png', 'txt', 'bmp']; 			   	           $("#FileUpload1").change(function () { 	               if ($.inArray($(this).val().split('.').pop().toLowerCase(), AllowedExtension) == -1) {                   alert("not allowed");                }  			    			   else {                    alert("thank you"); 				                 } 	           });   	 	       }); 	   </script> 	</head> 	<body> 	   <form id="form1"> 	   <div> 	       <h2>Validate File Upload using jQuery easy method</h2> 	       <input type ="file" ID="FileUpload1" /> 	        	   </div> 	   </form>	</body> 	</html>