If you are using visual studio.net for designing webpages in an asp.net web application, AND if you also have the habit of writing/editing/adding your own html input form tags in the code page AND if you also write seperate javascript for that page to validate the form inputs tags
then, dont forget to set an value for the Id tag for the newly typed input tags.

if not and if you happen parse that tag in javascript you will get the error saying document.[Your form name].[the input element name] has no properties.