Javascript将字符串格式的GUID转换为Base64

// Convert GUID string to Base-64 in Javascript
// by Mark Seecof, 2012-03-31

var hexlist = \'0123456789abcdef\';
var b64list = \'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\';

// GUID string with four dashes is always MSB first,
// but base-64 GUID\'s vary by target-system endian-ness.
// Little-endian systems are far more common.  Set le==true
// when target system is little-endian (e.g., x86 machine).
//
function guid_to_base64(g, le) {
    var s = g.replace(/[^0-9a-f]/ig, \'\').toLowerCase();
    if (s.length != 32) return \'\';

    if (le) s = s.slice(6, 8) + s.slice(4, 6) + s.slice(2, 4) + s.slice(0, 2) +
      s.slice(10, 12) + s.slice(8, 10) +
      s.slice(14, 16) + s.slice(12, 14) +
      s.slice(16);
    s += \'0\';

    var a, p, q;
    var r = \'\';
    var i = 0;
    while (i < 33) {
      a = (hexlist.indexOf(s.charAt(i++)) << 8) |
        (hexlist.indexOf(s.charAt(i++)) << 4) |
        (hexlist.indexOf(s.charAt(i++)));

      p = a >> 6;
      q = a & 63;

      r += b64list.charAt(p) + b64list.charAt(q);
    }
    r += \'==\';

    return r;
  } // guid_to_base64()

//EDIT
function tryConversion() {
  document.getElementById(\"result\").innerText = guid_to_base64(
    document.getElementById(\"input_guid\").value,
    document.getElementById(\"cb_le\").checked
  );
}

input[type=text] {
  font-family: monospace;
  font-size: 12px;
  width: 270px;
}

<div><label for=\"input_guid\">GUID</label> <input type=\"text\" maxlength=\"36\" id=\"input_guid\" value=\"83D95782-BDE4-466F-A490-46820D2B2CDC\" />
</div>
<div><label for=\"cb_le\">Little-Endian?</label> <input type=\"checkbox\" id=\"cb_le\" checked=\"checked\" /></div>
<hr />
<div><button onclick=\"javascript:tryConversion()\">Convert</button></div>
<div>Result: <span id=\"result\"></span></div>