Chrome Extension content_script at both document_start and document_end

Good day to everyone, as you can see I’m pretty new at Chrome extensions.

Can you run a script from content_scripts before and after the the DOM or page fully loads?

Like:

"content_scripts": [ {
    "matches": ["<all_url>"],
    "js": ["content.js"],
    "all_frames": true,
    "run_at": "document_start",
    "run_at": "document_end"
} ]

Or something like:

 "content_scripts": [ {
    "matches": ["<all_url>"],
    "js": ["content1.js"],
    "all_frames": true,
    "run_at": "document_start"
} ],
"content_scripts": [ {
    "matches": ["<all_url>"],
    "js": ["content2.js"],
    "all_frames": true,
    "run_at": "document_end"
} ]

Answer

You can have only one content_scripts entry, so it would be like:

"content_scripts": [{
    "matches": ["<all_urls>"],
    "js": ["content1.js"],
    "all_frames": true,
    "run_at": "document_start"
  },{
    "matches": ["<all_urls>"],
    "js": ["content2.js"],
    "all_frames": true,
    "run_at": "document_end"
}]

With this setting, content1.js would run at the beginning and content2.js at the end.