Chrome extension execCommand('copy') not copying - google-chrome

Question

Just started on a test chrome extension, basically I want to change the link on right click and send to clipboard, see:
background.js
var convert_buylink = function(event){
var parser = document.createElement('a');
parser.href = event.linkUrl;
parser.hostname = 'cart.local.co.nz';
parser.protocol = 'http';
var link = document.createElement('input');
//link.value = parse.href;
link.value = 'abc';
link.focus();
link.select();
document.execCommand('SelectAll');
document.execCommand("Copy")
}
chrome.contextMenus.create({title: "Copy Local BuyLink", contexts:["link"], onclick: convert_buylink});
manifest.json
{
"manifest_version": 2,
"name": "Local Buylink",
"description": "Changes buylink to local cart",
"version": "1.0",
"background": {
"scripts": ["background.js"]
},
"permissions": [
"contextMenus",
"tabs",
"clipboardWrite"
]
}
I have read about some results from google about the copy not working, all of them saying it doesn't work on content page, but according to documentation:
A background page will be generated by the extension system that includes each of the files listed in the scripts property.

Answer 1

You're creating the input inside a document object of the background page, which fails because the user gesture (context menu click) required for the copy command to work was performed in another document object: the web page. Also the element you create doesn't belong to document yet, it's a detached node.
Solution: create a hidden input inside the web page.
background.js:
function convert_buylink(info, tab) {
var parser = new URL(info.linkUrl);
parser.hostname = 'cart.local.co.nz';
parser.protocol = 'http';
clipboardCopy(parser.href);
}
function clipboardCopy(text) {
chrome.tabs.executeScript({code: "\
var input = document.createElement('input');\
input.value = '" + text.replace(/'/g, "\\'") + "';\
input.style.cssText = 'opacity:0; position:fixed';\
document.body.appendChild(input);\
input.focus();\
input.select();\
document.execCommand('Copy');\
input.remove();\
"});
}
manifest.json:
"permissions": [
..............
"activeTab"
],