Adding a code snippet with javascript function does not highlight code but after press spacebar or other key

[hermanvl]

Hello, I am using prism live in a textarea and it works fine but when I try to add a code snippet using a button onclick function (document.getElementById("content").innerHTML += header;), the code is added but invisible until i press spacebar or another key, then it shows up nicely highlighted as expected. Is there a way to force it so it is highlighted right away?
It works when I just paste it with ctrl-v but not with button onclick.
thanks

[dordchn]

You can trigger the highlighting code by dispatching the 'input' event on the textarea.

textarea.value = code;
textarea.dispatchEvent(new InputEvent("input"));