how to add focus to an element on form load.

[rongame]

hi guys

i have an element and i want to add js focus() on form load.

assuming
form = form_1
element = table__element_name

already tried to use the javascript code on the element = table__element_name

form_1.getElement('table__element_name').focus();

on event load.

its not working...

can anyone point me to the right direction. please thanks.