How to port extensions from Opera(chrome) to Firefox and also to Safari?

Question

Google Chrome

How to port extensions from Opera(chrome) to Firefox? When checking on the firefox site, a warning for the given lines and . (replaced from chrome to browser, but the problem was not solved)chrome.storage.local.get("adat", function(data) {chrome.storage.local.set({adat: texts});

Firefox add-on verification photo

What could be the problem and how to fix it?

content.js code

var forcopy = document.body.getElementsByClassName("pull-left btn btn-search-pill");
    var texts = [];
    for ( var cs = 0; cs < forcopy.length; cs++ ) {
        texts.push(forcopy[cs].textContent); 
    }
    chrome.storage.local.set({adat: texts});

popup.js code

chrome.storage.local.get("adat", function(data) {
    if(typeof data.adat == "undefined") {

    } else {
        document.getElementById("shuttertexts").textContent = data.adat;
        document.getElementById("shuttertexts").select();
    }
});

Any instructions for building or porting an extension to safari? Thanks in advance.

Answer 1

It also says - you need to specify id in the manifest:

...
"applications": {
    "gecko": {
        "id": "[email protected]"
    }
}
...