As you can see there http://omniasta.it/ is an js error:
Firefox : SyntaxError: JSON.parse: unexpected character at line 5 column 24 of the JSON data
Chrome: Uncaught SyntaxError: Unexpected token ,
If i remove the field with range that error not appear, i think that error stop all the javascript used to generate the range slider
I can’t see the range slider script loaded. Please check the Compatibility settings submenu for the Load the NoUI slider JS? option. If enabled, save the options and clear the site cache.