www.wysiwygwebbuilder.com

The following script does fire, and update the form, so I will use that.

document.getElementById("RefAthena").value = "40CH/12/12/2023/3776";

I dont know why innerText element does not work

Added another event after the ValidatePage1() as you suggested, but the field on the form still does not update.

ValidatePage1()

With an action of JavaScript

index.js, now contains function CopyOIC() { txt_CN2.value = txt_CN1.value txt_FN2.value = txt_FN1.value txt_SN2.value = txt_SN1.value txt_Tel2.value = txt_Tel1.value txt_MN2.value = txt_MN1.value txt_email2.value = txt_email1.value; } function ValidatePage1() { document.getElementById("RefAthena ...

I am calling the function on the onclick event of a button. ValidatePage1 should just display a message as a test.
I have moved the script into its own js file, rather than clutter up the HTML, I hope thats right.

I have added a small piece of javascript to the end of my page <script type="text/javascript"> function CopyOIC() { txt_CN2.value = txt_CN1.value txt_FN2.value = txt_FN1.value txt_SN2.value = txt_SN1.value txt_Tel2.value = txt_Tel1.value txt_MN2.value = txt_MN1.value txt_email2.value = txt_email1 ...