diff --git a/app/server/options.go b/app/server/options.go
index c04c553..b176110 100644
--- a/app/server/options.go
+++ b/app/server/options.go
@@ -71,7 +71,7 @@ func RunOptionsFromFlagSet(ctx context.Context, fs *flag.FlagSet) (*RunOptions,
 	}
 
 	uris_table = httpd.DefaultURIs()
-	uris_table.Root = root_u
+	uris_table.RootURL = root_u.String()
 
 	t_funcs := html_template.FuncMap{
 		"IsAvailable": sfom_funcs.IsAvailable,
diff --git a/app/server/server.go b/app/server/server.go
index e3bac58..b07c5b8 100644
--- a/app/server/server.go
+++ b/app/server/server.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net/http"
+	"net/url"
 
 	"github.com/aaronland/go-http-server"
 	"github.com/aaronland/go-http-server/handler"
@@ -47,6 +48,12 @@ func RunWithOptions(ctx context.Context, opts *RunOptions, logger *slog.Logger)
 	// START OF defer loading handlers (and all their dependencies) until they are actually routed to
 	// in case we are running in a "serverless" environment like AWS Lambda
 
+	path_urisjs, err := url.JoinPath(run_options.URIs.Static, "/javascript/whosonfirst.spelunker.uris.js")
+
+	if err != nil {
+		return fmt.Errorf("Failed to construct path for whosonfirst.spelunker.uris.js, %w", err)
+	}
+
 	handlers := map[string]handler.RouteHandlerFunc{
 
 		// WWW/human-readable
@@ -71,7 +78,7 @@ func RunWithOptions(ctx context.Context, opts *RunOptions, logger *slog.Logger)
 		// Static assets
 		run_options.URIs.Static: staticHandlerFunc,
 		// Run-time static assets
-		"/javascript/whosonfirst.spelunker.uris.js": urisJSHandlerFunc,
+		path_urisjs: urisJSHandlerFunc,
 
 		// API/machine-readable
 		run_options.URIs.ConcordanceNSFaceted:     hasConcordanceFacetedHandlerFunc,
diff --git a/static/javascript/whosonfirst.spelunker.uris.js b/static/javascript/whosonfirst.spelunker.uris.js
deleted file mode 100644
index 8772685..0000000
--- a/static/javascript/whosonfirst.spelunker.uris.js
+++ /dev/null
@@ -1,13 +0,0 @@
-var whosonfirst = whosonfirst || {};
-whosonfirst.spelunker = whosonfirst.spelunker || {};
-
-whosonfirst.spelunker.uris = (function(){
-
-    var self = {
-	abs_root_url: function(){
-	    return "/";
-	}
-    };
-
-    return self;
-})();
diff --git a/templates/javascript/whosonfirst.spelunker.uris.js b/templates/javascript/whosonfirst.spelunker.uris.js
index ef22a32..770196e 100644
--- a/templates/javascript/whosonfirst.spelunker.uris.js
+++ b/templates/javascript/whosonfirst.spelunker.uris.js
@@ -9,7 +9,14 @@ whosonfirst.spelunker.uris = (function(){
     var self = {
 	
 	abs_root_url: function(){
-	    return "/";
+
+	    var root = _table.root_url;
+
+	    if (! root.endsWith("/")){
+		root += "/";
+	    }
+	    
+	    return root;
 	},
 	
 	table: function(){
diff --git a/uris.go b/uris.go
index d1801a1..9732a0c 100644
--- a/uris.go
+++ b/uris.go
@@ -59,7 +59,7 @@ type URIs struct {
 	SVG                      string   `json:"svg"`
 	SVGAlt                   []string `json:"svg_alt"`
 
-	Root *url.URL `json:"root_url"`
+	RootURL string `json:"root_url"`
 }
 
 func (u *URIs) ApplyPrefix(prefix string) error {
@@ -170,16 +170,18 @@ func DefaultURIs() *URIs {
 
 func (uris_table *URIs) Abs(path string) (string, error) {
 
-	if uris_table.Root == nil {
-		return "#", fmt.Errorf("Root URL has not been assigned")
+	root_u, err := url.Parse(uris_table.RootURL)
+
+	if err != nil {
+		return "", fmt.Errorf("Failed to parse root URL, %w", err)
 	}
 
-	u := url.URL{}
-	u.Host = uris_table.Root.Host
-	u.Scheme = uris_table.Root.Scheme
-	u.Path = path
+	this_u := url.URL{}
+	this_u.Host = root_u.Host
+	this_u.Scheme = root_u.Scheme
+	this_u.Path = path
 
-	return u.String(), nil
+	return this_u.String(), nil
 }
 
 func URIForIdSimple(uri string, id int64) string {