1document.getElementById("cp_btn").addEventListener("click", copy_password);
2
3function copy_password() {
4    var copyText = document.getElementById("pwd_spn");
5    var textArea = document.createElement("textarea");
6    textArea.value = copyText.textContent;
7    document.body.appendChild(textArea);
8    textArea.select();
9    document.execCommand("Copy");
10    textArea.remove();
11}

1// Copy to clipboard on a click event
2document.querySelector("#copy-button").addEventListener('click', function() {
3	var reference_element = document.querySelector('#to-select-text');
4
5	var range = document.createRange();  
6	range.selectNodeContents(reference_element);
7
8	window.getSelection().addRange(range);
9
10	var success = document.execCommand('copy');
11	if(success)
12		console.log('Successfully copied to clipboard');
13	else
14		console.log('Unable to copy to clipboard');
15
16	window.getSelection().removeRange(range);
17});
18

1<span id="to-select-text">1111 - 2222 - 3333 - 4444</span>
2<button id="copy-button">Copy</button>