To prevent certain security exploits, Looker restricts which HTML tags, HTML tag attributes, and CSS properties are allowed in the html parameter, in custom welcome emails, and in text tiles and tile notes in dashboards.
Looker strips any HTML elements that aren’t supported from the rendered HTML. For instance, the following HTML has unsupported HTML tags:
<div class="pretty"><badtag></badtag></div>
Looker will render this as:
<div class="pretty"></div>
As another example, the following HTML has unsupported HTML attributes:
<div class="pretty" badattr="uh-oh"></div>
Looker will render this as:
<div class="pretty"></div>
HTML sanitization is on by default and can’t be edited.
Allowed HTML tags
Only certain HTML tags will be rendered in the browser. Any other tags will be stripped from rendered HTML.
Here is the list of HTML tags that Looker supports:
a abbr acronym address area article aside audio b bdi bdo big blockquote br button canvas caption center cite code col colgroup datalist dd del details dfn dir div dl dt em fieldset figcaption figure font footer h1 h2 h3 h4 h5 h6 header ins hr i img kbd label legend li map mark menu meter nav ol output p pre q s samp section small source span strike strong sub summary sup table tbody td tfoot th thead time tr track tt u ul var video Allowed HTML tag attributes
Only certain HTML attributes will be rendered in the browser. Any other attributes will be stripped from rendered HTML. This also applies to the CSS properties for HTML style tags.
Here is the list of HTML attributes that Looker supports:
abbr accept accept-charset accesskey action align alt autoplay axis border cellpadding cellspacing char charoff charset checked cite class clear color cols colspan compact controls controlslist coords datetime dir disabled enctype for frame headers height href hreflang hspace id ismap label lang longdesc loop loopcount loopend loopstart maxlength media method multiple muted name nohref noshade nowrap poster preload prompt readonly rel rev rows rowspan rules scope selected shape size span src start style summary tabindex target title type usemap valign value vspace width xml:lang Allowed CSS Properties for HTML style Tags
Here is the list of allowed CSS properties that Looker supports:
-moz-border-radius -moz-border-radius-bottomleft -moz-border-radius-bottomright -moz-border-radius-topleft -moz-border-radius-topright -moz-box-shadow -moz-outline -moz-outline-color -moz-outline-style -moz-outline-width -o-text-overflow -webkit-border-bottom-left-radius -webkit-border-bottom-right-radius -webkit-border-radius -webkit-border-radius-bottom-left -webkit-border-radius-bottom-right -webkit-border-radius-top-left -webkit-border-radius-top-right -webkit-border-top-left-radius -webkit-border-top-right-radius -webkit-box-shadow azimuth background background-attachment background-color background-image background-position background-repeat border border-bottom border-bottom-color border-bottom-left-radius border-bottom-right-radius border-bottom-style border-bottom-width border-collapse border-color border-left border-left-color border-left-style border-left-width border-radius border-right border-right-color border-right-style border-right-width border-spacing border-style border-top border-top-color border-top-left-radius border-top-right-radius border-top-style border-top-width border-width box-shadow caption-side clear color cue cue-after cue-before cursor direction display elevation empty-cells float font font-family font-size font-stretch font-style font-variant font-weight height image() letter-spacing line-height linear-gradient() list-style list-style-image list-style-position list-style-type margin margin-bottom margin-left margin-right margin-top max-height max-width min-height min-width outline outline-color outline-style outline-width overflow padding padding-bottom padding-left padding-right padding-top pause pause-after pause-before pitch pitch-range quotes radial-gradient() rect() repeating-linear-gradient() repeating-radial-gradient() rgb() rgba() richness speak speak-header speak-numeral speak-punctuation speech-rate stress table-layout text-align text-decoration text-indent text-overflow text-shadow text-transform text-wrap unicode-bidi vertical-align voice-family volume white-space width word-spacing word-wrap