function _onChangeFile(sNamespace){
        var htElement = htElements[sNamespace];
        var sFileName = _getBasename(htElement.welInputFile.val());
        if(!sFileName || sFileName === ""){
            return;
        }

        _uploadFile(htElement.welInputFile[0].files || htElement.welInputFile[0], sNamespace);
    }
change event handler on input[type="file"]

@param {String} sNamespace