JavaScript run by AppleScript to click button and fill text in Safari
So unlike Chrome where you can just adding few line with different JS code,
in safari you have to added for each code do JavaScript and mention the document / tab

e.g :

tell application "Safari"
    delay 0.1
    do JavaScript "document.getElementById('accountEnabledSelection').value=1" in current tab of window 1
    do JavaScript "document.getElementsByName('demo')[0].click();" in current tab of window 1


end tell