css border color opacity code example

Example 1: css border opacity

div {
    border: 1px solid rgba(255, 0, 0, .5);
    -webkit-background-clip: padding-box; /* for Safari */
    background-clip: padding-box; /* for IE9+, Firefox 4+, Opera, Chrome */
}

Example 2: border color transparent

border-color's transparent property

*** border-color: rgba(111,111,111,0);

rgba(111,111,111,0)
this will invisible your border color.
because that rgba color has property to invisible the border or font of color
if i am correct. other-wise correct my mistake thanks

Example 3: how to give opacity to border

border: 1px solid rgba(255, 0, 0, .5);