Check whether user has a Chrome extension installed

Question

I am in the process of building a Chrome extension, and for the whole thing to work the way I would like it to, I need an external JavaScript script to be able to detect if

Answer 1

Here is an other modern approach:

const checkExtension = (id, src, callback) => {
    let e = new Image()
    e.src = 'chrome-extension://'+ id +'/'+ src
    e.onload = () => callback(1), e.onerror = () => callback(0)
}

// "src" must be included to "web_accessible_resources" in manifest.json
checkExtension('gighmmpiobklfepjocnamgkkbiglidom', 'icons/icon24.png', (ok) => {
    console.log('AdBlock: %s', ok ? 'installed' : 'not installed')
})
checkExtension('bhlhnicpbhignbdhedgjhgdocnmhomnp', 'images/checkmark-icon.png', (ok) => {
    console.log('ColorZilla: %s', ok ? 'installed' : 'not installed')
})