HTML Text before copy [closed]

EDIT: Edit 2 should answer to the question

<a id="demo" class="button cta-button" onclick="copyToClipboard(document.getElementById('demo').innerHTML)">
Server Ip Here
</a> 

Everything between " is rendered as text.

Example:

var text="value";
console.log(text); //Will render "value"
console.log("text"); //Will render "text"

copyToClipboard(document.getElementById('demo').innerHTML) is then executed with arg document.getElementById('demo').innerHTML which is a string here.

Case 1
Your <a> tags displays the value of your IP server

onclick="copyToClipboard("+document.getElementById('demo').innerHTML+")"

Case 2
Your <a> tags hides the IP of the server

var ip = "ip address";  //In your javascript file

onclick="copyToClipboard("+ip+")"

Warning: Your ip value must be declared in the top of your HTML file in <script> tag or a file before the html is rendered in your body, else ip value is null and your <a> tag will have a wrong value onclick="copyToClipboard()"

EDIT 2
Considering the script part okay

<a id="demo" class="button cta-button" onclick="copyToClipboard('192.168.1.1')">
Click here to copy ip
</a> 

document.getElementById('demo').innerHTML gives you everything inside your tags <a id="demo"> tags, so in your example it was “Server Ip Here”. However that is not what you were expecting, so you can change it by the value of your IP server.

This works:

<script>
    function copyToClipboard(text) {
         window.prompt("Copy to clipboard: Ctrl+C, Enter", text);
      }
</script>

<a id="demo" class="button cta-button" onclick="copyToClipboard('192.168.1.1')">
     Click here to copy ip
</a> 

About <a> tags, give a try to the Try it yourself to understand how do they work
http://www.w3schools.com/tags/tag_a.asp