Unblu 4.1

Embedded Co-Browsing Limitations


1. Overview

Please see below an overview of limitations and gotchas when using embedded co-browsing in your website. To get more details about a certain topic click the link in the overview (if available).

Note that the list is not necessarily complete. It reflects the limitations known at the time of writing. The list is extended whenever future issues are reported or examined with our own tests.

Technology / Design Patterns Works with embedded co-browsing
Scalable Vector Graphics (SVG) (tick) (with some limitations)
  svg animation (warning) (animations on visitor and agent side are not in sync)
HTML 5 (tick) (with some limitations - see below)
  <input> new types (date, color, range, number) (warning) (input fields are rendered by the browser. Thus, look and feel may differ when visitor and agent use different browsers)
  <canvas> (tick) (see limits about tainted canvas; canvas can be disabled for security reasons)
  <video>, <audio> (minus)
HTML Framesets (minus) (iframes are supported - for cross origin iframes: see below)
CSS (tick) (with some limitations - see below)
  css selectors level 1 (tick)
  css selectors level 2 (tick)
  css selectors level 3 (warning) (mostly supported)
  css selectors level 4 (minus) (current status with W3C is working draft - not an official specification yet)
  css pseudo classes (warning) (elements shown when hovering on visitor side are not displayed on agent side)
  browser specific properties (-moz-gradient etc) (warning) (not supported in on premise setups with Resource History turned on)
  Internet Explorer "filters" (warning) (partly supported but deprecated)
  css function style property values

(warning) supported are:

Font functions defined in

stylistic(), styleset(), character-variant(), swash(), ornaments,annotation()

General functions as defined in

linear-gradient(), radial-gradient(), repeating-linear-gradient(), repeating-radial-gradient()

css shapes according to

inset(), circle(), ellipse(), polygon()

2d transform functions as defined in

matrix(), translate(), translateX(), translateY(), scale(), scaleX(), scaleY(), rotate(), skew(), skewX(), skewY()

3d transform functions as defined in

matrix3d(), translate3d(), translateZ(), scale3d(), scaleZ(), rotate3d(), rotateX(), rotateY(), rotateZ(), perspective()

filter functions as defined in

blur(), brightness(), contrast(), drop-shadow(), grayscale(), hue-rotate(), invert(), opacity(), saturate(), sepia()

General / basic (long standing) functions in CSS:

attr(), counter(), counters(), rect(), rgb(), rgba(), url()


Currently not supported are:

calc() (only editors draft available)


hsl(), hsla()


  css3 animations (warning) (not in sync between visitor and agent)
Cross Origin (x-origin) (tick) (see details below)
  x-origin iframes (tick) (unblu snippet must be contained in all iframe pages)
  Cross Origin Resource Sharing (CORS) (tick)
  Changing protocol, origin or port in a running co-Browsing Session (warning)(works with limitations when only subdomains are changed)
Javascript Navigation (warning)(page elements shown on "mouseover" cannot be triggered on agent side)
Javascript alert, confirm, prompt (minus) (all operations that stop javascript entirely lead to problems with unblu)
Single Page Application (SPA) (tick)
Internet Explorer Conditional Comments (minus)
Continuous Scrolling (Infinite Scroll) (warning) (not working on agent side; use "load more" instead)
Carousel (warning) (agent cannot interact with carousel)
Captcha (warning) (depending on captcha technology, agent may see another captcha than visitor)
Adobe Flash (minus) (banner or videos may work but visitor and agent are out of sync)
Microsoft Silverlight (minus) (banner or videos may work but visitor and agent are out of sync)
Java Applets (minus)
Active X Objects (minus) (disabled for security reasons)