# Uncaught TypeError: Cannot read property 'length' of undefined - Kibana Dash board **URL:** \ **Category:** Kibana\ **Created:** [January 8, 2018, 6:44am UTC](https://discuss.elastic.co/t/uncaught-typeerror-cannot-read-property-length-of-undefined-kibana-dash-board/114452 "2018-01-08T06:44:14Z")\ **Posts on this page:** 4\ **Page:** 1

**Author:** ![ruranga](https://avatars.discourse-cdn.com/v4/letter/r/97f17d/32.png) [@ruranga](https://discuss.elastic.co/u/ruranga)\ **Post date:** [January 8, 2018, 6:44am UTC](https://discuss.elastic.co/t/uncaught-typeerror-cannot-read-property-length-of-undefined-kibana-dash-board/114452/1 "2018-01-08T06:44:15Z")

I'm rotating dashboards using simple HTML/Js code running on Tomcat. Code is as follows body, html { height: 100%; overflow: hidden; padding: 0; margin: 0; } ``` .page { top: 0; left: 0; width: 100%; min-height: 100%; position: absolute; display: none; overflow: hidden; border: 0; } .currentPage { display: block; }

``` But when loading above using Chrome following error appears for some of the dash boards ![kibana_error](https://us1.discourse-cdn.com/elastic/original/3X/8/5/855b74906a99e35b4f92c8dee74e75f56fca4adf.png) Can some one please help me? Thanks in advance ---

**Author:** ![weltenwort](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/weltenwort/32/53885_2.png) [@weltenwort](https://discuss.elastic.co/u/weltenwort)\ **Post date:** [January 8, 2018, 3:04pm UTC](https://discuss.elastic.co/t/uncaught-typeerror-cannot-read-property-length-of-undefined-kibana-dash-board/114452/2 "2018-01-08T15:04:17Z")

Hi @ruranga, it is a known effect in some browsers that iframes loaded in invisible container elements are rendered with a width and height of 0, which confuses the dashboards. The common solution for that is to lazily load the iframes when they first become visible. You could, for example, replace the `src` attribute on your `iframe`s with `data-src` and copy it over to the `src` in your javascript when `currentPage` is first applied. ---

**Author:** ![ruranga](https://avatars.discourse-cdn.com/v4/letter/r/97f17d/32.png) [@ruranga](https://discuss.elastic.co/u/ruranga)\ **Post date:** [January 10, 2018, 3:52am UTC](https://discuss.elastic.co/t/uncaught-typeerror-cannot-read-property-length-of-undefined-kibana-dash-board/114452/3 "2018-01-10T03:52:23Z")

Thanks for the help. I will try 👍 ---

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [February 7, 2018, 3:52am UTC](https://discuss.elastic.co/t/uncaught-typeerror-cannot-read-property-length-of-undefined-kibana-dash-board/114452/4 "2018-02-07T03:52:25Z")

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