merged from https://github.com/wordnik/swagger-ui/pull/642

src/main/coffeescript/SwaggerUi.coffee

@@ -39,6 +39,14 @@ class SwaggerUi extends Backbone.Router
     # Event handler for when the baseUrl/apiKey is entered by user
     @headerView.on 'update-swagger-ui', (data) => @updateSwaggerUi(data)
 
+  # Set an option after initializing
+  setOption: (option,value) ->
+      @options[option] = value
+
+  # Get the value of a previously set option
+  getOption: (option) ->
+      @options[option]
+
   # Event handler for when url/key is received from user
   updateSwaggerUi: (data) ->
     @options.url = data.url

src/main/coffeescript/view/MainView.coffee

@@ -27,8 +27,15 @@ class MainView extends Backbone.View
     if !@model.info.version
       @model.info.version = @model.apiVersion
 
-    if @model.url.indexOf('http://localhost') is -1 and @model.swaggerVersion is 2
+    if "validatorUrl" of opts.swaggerOptions
+      # Validator URL specified explicitly
+      @model.validatorUrl = opts.swaggerOptions.validatorUrl
+    else if @model.url.match(/https?:\/\/localhost/) and @model.swaggerVersion is 2
+      # Localhost override
       @model.validatorUrl = @model.url
+    else
+      # Default validator
+      @model.validatorUrl = "http://online.swagger.io/validator"
  
   render: ->
     # Render the outer container for resources