How to change "instructions" value of a element via script?

[R B]

Hello Everyone,

How can i set the "Instructions" value of an element via script?  my requirement is to change this value on the fly based on the account. 

I am not sure which property or method to use to set this value? Any help please? 

[R B]

Thanks again Mike. i add the script OnChange for the field and it appears to work and stick..  i wonder why this message disappeared when configured with on "ON LOAD" and why it is not disappearing for field "On Change" 

[Mike_R]

Do you have any other client scripts or UI policies that could be conflicting?

[R B]

Not where i am setting g_form.showFieldMsg().. 

[Mike_R]

But they could possibly be clearing field messages. Maybe try disabling them to help with troubleshooting.