unresponsive script with firefox

Hi guys..

i m getting Unresponsive Script in firefox 1.0.5.3...i know i can set dom.max_script_run_time as 20 ..through about:config ..

but it is the part of user..and i want to set this value through javascript code ..

is it possible ...
pls let me know

Thanks
Pratik_soft@yahoo.com