Not set a disabled idea, but disable the button as YUI do.
var budgets_menu = [
{ text: _("Display budgets"), url: "/cgi-bin/koha/admin/aqbudgets.pl?budget_period_id=<!-- TMPL_VAR NAME="budget_period_id" -->" },
{ text: _("New budget for '<!-- TMPL_VAR NAME="budget_period_description" -->'"), url: "/cgi-bin/koha/admin/aqbudgets.pl?op=add_form&budget_period_id=<!-- TMPL_VAR NAME="budget_period_id" -->"
- <!-- TMPL_IF NAME="budget_period_locked" -->, id:'disabled' <!-- /TMPL_IF -->
- <!-- TMPL_UNLESS NAME="CAN_user_acquisition_budget_add_del" -->, id:'disabled' <!-- /TMPL_UNLESS -->
+ <!-- TMPL_IF NAME="budget_period_locked" -->, disabled:true<!-- /TMPL_IF -->
+ <!-- TMPL_UNLESS NAME="CAN_user_acquisition_budget_add_del" -->, disabled:true <!-- /TMPL_UNLESS -->
},
]