Global.String.prototype.debase64 ()
returns the decoded string using the base64 algorithm

Sourcecode in /home/hannes/helma/modules/core/String.js:
637:   String.prototype.debase64 = function() {
638:       var bytes = new Packages.sun.misc.BASE64Decoder().decodeBuffer(this);
639:       return String(new java.lang.String(bytes));
640:   }