Add CSS to pages through a CSS file

Question

I was wondering if it was possible to add CSS to pages through a CSS file, similarly to adding JS to pages through a JS file (contentscript). So, I could just define what pages said CSS file would work on and then it would take effect just like a contentscript. I understand that it is possible to add CSS through a JavaScript file, but it would be more convenient to do it this way instead if possible. If it's not possible, then of course I must use contentscript, but I would first like to know before I rule out any possibilities. I've searched and received no answers - either I'm searching wrong or it really isn't possible. Chrome extensions have come a long way, though, so I'm still not ruling it out until someone who knows can tell me yes & how or no. Thanks for any responses.

Answer 1

Your manifest file must contain a content script pointing to a CSS file, that will load when a url matches your selected url fields...

"content_scripts": [ {
   "css": [ "scrollbars.css" ],
   "matches": [ "http://www.google.com/*" ]
} ],

This is the same method you would use to inject javascript code, except you would point to a js file instead...

More information here...

Answer 2

similarly like we add JavaScript in content_scripts also add CSS

Method-1

"content_scripts": [
{
    "matches": ["<all_urls>"],
    "css": ["css/style.css"],
    "js": ["jquery-1.10.2.min.js","content.js","my.min.js"]
}],

add one more thing on web_accessible_resources

"web_accessible_resources": [
    "css/style.css"
  ]

if you used any external JavaScript then also add URL in permission tab.

"permissions": ["tabs", <all_urls>","http://*/","http://example.com/"]

Method-2

also same this thing using vai programming injection and insertCSS().

chrome.tabs.insertCSS(integer tabId, object details, function callback)

NOTE : web_accessible_resources add .css is not mandatory but as of chrome extension forum is good practice.

Answer 3

manifest.json:

"web_accessible_resources": [
      "css/style.css"
],

content-script.js:

var a = chrome.extension.getURL("css/style.css");
$('<link rel="stylesheet" type="text/css" href="' + a + '" >').appendTo("head");

My extension using jQuery