Fix CSP for element hiding (#314)

Author: jonathanKingston

src/features/element-hiding.js

@@ -224,7 +224,9 @@ function extractTimeoutRules (rules) {
  * @param {string} rules[].type
  */
 function injectStyleTag (rules) {
-    const styleTag = document.createElement('style')
+    const styleTag = document.createElement('link')
+    styleTag.setAttribute('rel', 'stylesheet')
+    styleTag.setAttribute('type', 'text/css')
     let styleTagContents = ''
 
     rules.forEach((rule, i) => {
@@ -236,7 +238,7 @@ function injectStyleTag (rules) {
     })
 
     styleTagContents = styleTagContents.concat('{display:none!important;min-height:0!important;height:0!important;}')
-    styleTag.innerText = styleTagContents
+    styleTag.href = 'data:text/css,' + encodeURIComponent(styleTagContents)
 
     document.head.appendChild(styleTag)
 }