In Kendo UI async file uploading there is no option to make some client side validation like: No of files you can upload at a time Size of the file Extension of your uploading file So, how we can achieve this ? So, to know that see the javascript code snippet below. I am going to explain that. $ ( '#selectedFiles-edit-win' ). kendoUpload ({ multiple : true , localization : { select : 'Select File(s)' }, async : { saveUrl : "/CFCS/AjaxFactory.cfc?method=uploadFile" , removeUrl : "/CFCS/AjaxFactory.cfc?method=cancelUploadedFile" , autoUpload : true }, select : function ( e ) { var files = e . files ; if ( files . length > 10 ) { alert ( "Maximum 10 files can be uploaded at a time." ); e . preventDefault (); return false ; } for ( var fileCntr = 0 ; fileCntr < files . length ; fileCntr ++ ) { if ( files [ fileCntr ]. s...