manifest.json

{
"manifest_version": 2,
    "name": "a",
    "description": "b",
    "version": "0.1",
    "content_scripts": [
        {
            "matches": [
                "http://192.168.1.1/*",
            ],
            "js": [
                "content.js"
            ],
            "run_at": "document_start"
        }
    ]
}