chrome/common/extensions/docs/templates/articles/manifest/event_rules.html

   1 <h1>event_rules</h1>
   2
   3 <p>
   4 The <code>event_rules</code> manifest property provides a mechanism to add rules that intercept, block, or modify web requests in-flight using <a href="../declarativeWebRequest">declarativeWebRequest</a> or take actions depending on the content of a page, without requiring permission to read the page's content using <a href="../declarativeContent">declarativeContent</a>.
   5 </p>
   6
   7 <h2 id="translation">Translating rules from javascript to manifest</h2>
   8
   9 <p>
  10 The following defines a rule to display a page action if the current page has a video css tag in javascript:
  11 </p>
  12
  13 <pre data-filename="example.js">
  14 chrome.<b>declarativeContent.onPageChanged</b>.addRules([{
  15   actions: [
  16     new chrome.<b>declarativeContent.ShowPageAction</b>()
  17   ],
  18   conditions: [
  19     new chrome.<b>declarativeContent.PageStateMatcher</b>(
  20         <b>{css: ["video"]}</b>
  21     )
  22   ]
  23 }]);
  24 </pre>
  25
  26 <p>
  27 This is the same definition in the manifest:
  28 </p>
  29
  30 <pre data-filename="manifest.json">
  31 {
  32   "name": "Sample {{platform}}",
  33   "event_rules": [{
  34     "event": <b>"declarativeContent.onPageChanged"</b>,
  35     "actions": [{
  36       "type": <b>"declarativeContent.ShowPageAction"</b>
  37     }],
  38     "conditions": [{
  39       "type": <b>"declarativeContent.PageStateMatcher"</b>,
  40       <b>"css": ["video"]</b>
  41     }]
  42   }],
  43   ...
  44 }
  45 </pre>