Single-element data array, choose six randomly

The JavaScript code below creates a single-element array, choosing 6 different elements from array.

var oStrings =
 [
"PG3032901074056",
"PG3052321074056",
"PG3062641074056",
"PG3082651074056",
"PG3182821075056",
];

var a = oStrings[Math.floor(oStrings.length * (Math.random()))];
var b = oStrings[Math.floor(oStrings.length * (Math.random()))];
var c = oStrings[Math.floor(oStrings.length * (Math.random()))];
var d = oStrings[Math.floor(oStrings.length * (Math.random()))];
var e = oStrings[Math.floor(oStrings.length * (Math.random()))];
var f = oStrings[Math.floor(oStrings.length * (Math.random()))];
$prop.set("MessageClip", "ecard1", a);
$prop.set("MessageClip", "ecard2", b);
$prop.set("MessageClip", "ecard3", c);
$prop.set("MessageClip", "ecard4", d);
$prop.set("MessageClip", "ecard5", e);
$prop.set("MessageClip", "ecard6", f);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + a);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + b);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + c);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + d);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + e);
$context.result.postMessage($context.result.LEVEL_INFO, "ecard: " + f);