Como copiar conteúdo de duas div's ao mesmo tempo?

Esse é o HTML

<div id="markup">
 Text that can be copied or selected with cross browser support.
</div>
<br><br>

não copiar esse texto

<br><br>
<div id="markup2">
 Copiar o texto 2
</div>
<br><br>

<button id="botaodecopiar1">copiar!</button>

	 

	E esse é o Javascript>

	 

<script type="text/javascript">
 function selectElementContents(el)

{ // Copy textarea, pre, div, etc.

	if (document.body.createTextRange) {
 // IE
 var textRange = document.body.createTextRange();
 textRange.moveToElementText(el);
 textRange.select();
 textRange.execCommand("Copy");
 }
	else if (window.getSelection && document.createRange) {
 // non-IE
 var range = document.createRange();
 range.selectNodeContents(el);
 var sel = window.getSelection();
 sel.removeAllRanges();
 sel.addRange(range);
 try {
 var successful = document.execCommand('copy');
 var msg = successful ? 'successful' : 'unsuccessful';
 console.log('Copy command was ' + msg);
 } catch(err) {
 console.log('Oops, unable to copy');
 }
 }
} // end function selectElementContents(el)

function make_copy_button(el)

{

	var botaodecopiar = document.getElementById('botaodecopiar1');
	botaodecopiar.onclick = function() { selectElementContents(el); };

	if (document.queryCommandSupported("copy") || parseInt(navigator.userAgent.match(/Chrom(e|ium)\/([0-9]+)\./)[2]) >= 42)
	{
 // Copy works with IE 4+, Chrome 42+, Firefox 41+, Opera 29+
 botaodecopiar.value = "Copy to Clipboard";
	}
	else
	{
 // Select only for Safari and older Chrome, Firefox and Opera
 botaodecopiar.value = "Select All (then press CTRL+C to Copy)";
	}
}
var elem = document.getElementById("markup");
var elem2 = document.getElementById("markup2");
make_copy_button(elem2);
</script>