How do I add dynamic javascript to the head tag from a string, not a file?

Question

I am using Javascript to generate additional custom javascript and then adding it to the HEAD tag. The code below works great adding a javascript file, but what if the script is in a variable just generated?

var scriptTag = document.createElement("script");
scriptTag.setAttribute("type", "text/javascript");
scriptTag.setAttribute("src", "myfile.js");
document.getElementsByTagName("head")[0].appendChild(scriptTag);

Thank you for your attention.

Answer 1

   // script text
var txt = "alert('foo');";

var scriptTag = document.createElement("script");
scriptTag.setAttribute("type", "text/javascript");

   // append it in a text node
scriptTag.appendChild(document.createTextNode(txt));
document.getElementsByTagName("head")[0].appendChild(scriptTag);

---

FWIW, you don't need a script tag for this. You can use the Function constructor instead.

var txt = "alert('foo');";

Function(txt)();

Answer 2

var scriptTag = document.createElement("script");
scriptTag.setAttribute("type", "text/javascript");

scriptTag.innerHTML = "What you want here";///....

document.getElementsByTagName("head")[0].appendChild(scriptTag);

Live DEMO