diff --git a/main.rkt b/main.rkt
index 7027e0d..11ac98c 100644
--- a/main.rkt
+++ b/main.rkt
@@ -5,6 +5,7 @@
          "private/config.rkt"
          "private/diff.rkt"
          "private/info.rkt"
+         "private/utils.rkt"
          simple-log
          racket/string
          net/sendurl
@@ -62,9 +63,7 @@
 ; result : The entered line or an EOF object.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-prompt p)
-  (display p)
-  (flush-output)
-  (read-line))
+  (input-prompt p))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Add --porcelain to a Git argument list when it is absent.
diff --git a/private/diff.rkt b/private/diff.rkt
index fe93843..9f726fb 100644
--- a/private/diff.rkt
+++ b/private/diff.rkt
@@ -6,10 +6,13 @@
          xml
          racket/string
          "config.rkt"
+         "utils.rkt"
          )
 
 (provide diff->html
-         show->html)
+         show->html
+         config-diff2html
+         )
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Helper functions
@@ -57,6 +60,39 @@
 ;; Exported functions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(define (config-diff2html)
+
+  (define (checker f)
+    (λ (inp)
+      (let ((url (string-trim inp)))
+        (if (string=? url "")
+            (f)
+            (if (valid-http-or-file-url? url)
+                url
+                (begin
+                  (displayln "! Not a valid url, please input a valid url")
+                  #f)))))
+    )
+
+  (define (inp name f)
+    (input-prompt (string-join
+                   (list
+                    (format "Give the url for the ~a" name)
+                    "Enter keeps the current value:"
+                    (string-append " - " (f))
+                    ">")
+                   "\n")
+                  #:loop-until (checker f)))
+    
+    (let ((h-css (inp "Highlighting CSS" highlight-css))
+          (d-css (inp "Diff2Html CSS" diff2html-min-css))
+          (d-js (inp "Diff2Html UI Javascript" diff2html-ui-min-js))
+          )
+      (cfg-set! 'diff 'highlight-css h-css)
+      (cfg-set! 'diff 'diff2html-min-css d-css)
+      (cfg-set! 'diff 'diff2html-ui-min-js d-js))
+  )
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Render a Git diff in a temporary HTML file.
 ; pre    : diff is a unified Git diff string.
diff --git a/private/utils.rkt b/private/utils.rkt
index d3b5556..c85e595 100644
--- a/private/utils.rkt
+++ b/private/utils.rkt
@@ -1,4 +1,32 @@
 #lang racket/base
 
-(provide config)
+(require net/url)
 
+(provide input-prompt
+         valid-http-or-file-url?
+         )
+
+(define (input-prompt p #:loop-until [until (λ (x) x)])
+  (let loop ()
+    (display p)
+    (flush-output)
+    (let ((inp (read-line)))
+      (let ((i (until inp)))
+        (if i
+            i
+            (loop)))
+      )
+    )
+  )
+
+
+
+(define (valid-http-or-file-url? value)
+  (if (not (string? value))
+      #f
+      (with-handlers ([exn:fail? (λ (exn) #f)])
+        (let ((url (string->url value)))
+          (and
+           (member (url-scheme url) '("http" "https" "file"))
+           (string? (url-host url))
+           (not (string=? (url-host url) "")))))))
\ No newline at end of file