The above text says that enctype was introduced in IE 6, and that you should only use encoding if want backwards compatibility. However if you are using a dynamically created iframe to send a “multipart/form-data” form, enctype just doesn’t work, if you follow the script with the debugger you will see that the property actually changes, however the server receives “application/x-www-form-urlencoded”, that happens even in IE 7. The only way you can avoid this is using encoding instead of enctype.