sS hjs_hexencode() {
  ret hjavascript([[
  String.prototype.hexencode = function(){
    var hex, i;

    var result = "";
    for (i=0; i<this.length; i++) {
        hex = this.charCodeAt(i).toString(16);
        result += ("000"+hex).slice(-4);
    }

    return result
}]]);
}

Began life as a copy of #1013837