How refresh is different from clicking "Go"; Refresh; F5; Ctrl+F5; Ctrl+R

cached refresh:
    form:
        input retains value
        textarea retains value
        select retains selected
    img:
        revalidate request sent (slower)

go:
    form:
        input value reset
        textarea value reset
        select selected reset
    img:
        HTTP_IF_MODIFIED_SINCE (faster)

no cache refresh:
    form:
        input value reset
        textarea value reset
        select selected reset