How to remove/hide select options from select-list

Answer 1

To hide it, wrap it with a span tag.

$( "#selectlist option[value=4]" ).wrap( "" );

To show it, unwrap the span tag if it has one.

if ( $( "#selectlist option[value=4]" ).parent().is( "span" ) ){
    $( "#selectlist option[value=4]" ).unwrap();
}